Index: head/sys/kern/kern_lock.c =================================================================== --- head/sys/kern/kern_lock.c (revision 228423) +++ head/sys/kern/kern_lock.c (revision 228424) @@ -1,1459 +1,1462 @@ /*- * Copyright (c) 2008 Attilio Rao * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice(s), this list of conditions and the following disclaimer as * the first lines of this file unmodified other than the possible * addition of one or more copyright notices. * 2. Redistributions in binary form must reproduce the above copyright * notice(s), this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH * DAMAGE. */ #include "opt_adaptive_lockmgrs.h" #include "opt_ddb.h" #include "opt_kdtrace.h" #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #ifdef DEBUG_LOCKS #include #endif #include #include #include #ifdef DDB #include #endif CTASSERT(((LK_ADAPTIVE | LK_NOSHARE) & LO_CLASSFLAGS) == (LK_ADAPTIVE | LK_NOSHARE)); CTASSERT(LK_UNLOCKED == (LK_UNLOCKED & ~(LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS))); #define SQ_EXCLUSIVE_QUEUE 0 #define SQ_SHARED_QUEUE 1 #ifndef INVARIANTS #define _lockmgr_assert(lk, what, file, line) #define TD_LOCKS_INC(td) #define TD_LOCKS_DEC(td) #else #define TD_LOCKS_INC(td) ((td)->td_locks++) #define TD_LOCKS_DEC(td) ((td)->td_locks--) #endif #define TD_SLOCKS_INC(td) ((td)->td_lk_slocks++) #define TD_SLOCKS_DEC(td) ((td)->td_lk_slocks--) #ifndef DEBUG_LOCKS #define STACK_PRINT(lk) #define STACK_SAVE(lk) #define STACK_ZERO(lk) #else #define STACK_PRINT(lk) stack_print_ddb(&(lk)->lk_stack) #define STACK_SAVE(lk) stack_save(&(lk)->lk_stack) #define STACK_ZERO(lk) stack_zero(&(lk)->lk_stack) #endif #define LOCK_LOG2(lk, string, arg1, arg2) \ if (LOCK_LOG_TEST(&(lk)->lock_object, 0)) \ CTR2(KTR_LOCK, (string), (arg1), (arg2)) #define LOCK_LOG3(lk, string, arg1, arg2, arg3) \ if (LOCK_LOG_TEST(&(lk)->lock_object, 0)) \ CTR3(KTR_LOCK, (string), (arg1), (arg2), (arg3)) #define GIANT_DECLARE \ int _i = 0; \ WITNESS_SAVE_DECL(Giant) #define GIANT_RESTORE() do { \ if (_i > 0) { \ while (_i--) \ mtx_lock(&Giant); \ WITNESS_RESTORE(&Giant.lock_object, Giant); \ } \ } while (0) #define GIANT_SAVE() do { \ if (mtx_owned(&Giant)) { \ WITNESS_SAVE(&Giant.lock_object, Giant); \ while (mtx_owned(&Giant)) { \ _i++; \ mtx_unlock(&Giant); \ } \ } \ } while (0) #define LK_CAN_SHARE(x) \ (((x) & LK_SHARE) && (((x) & LK_EXCLUSIVE_WAITERS) == 0 || \ ((x) & LK_EXCLUSIVE_SPINNERS) == 0 || \ curthread->td_lk_slocks || (curthread->td_pflags & TDP_DEADLKTREAT))) #define LK_TRYOP(x) \ ((x) & LK_NOWAIT) #define LK_CAN_WITNESS(x) \ (((x) & LK_NOWITNESS) == 0 && !LK_TRYOP(x)) #define LK_TRYWIT(x) \ (LK_TRYOP(x) ? LOP_TRYLOCK : 0) #define LK_CAN_ADAPT(lk, f) \ (((lk)->lock_object.lo_flags & LK_ADAPTIVE) != 0 && \ ((f) & LK_SLEEPFAIL) == 0) #define lockmgr_disowned(lk) \ (((lk)->lk_lock & ~(LK_FLAGMASK & ~LK_SHARE)) == LK_KERNPROC) #define lockmgr_xlocked(lk) \ (((lk)->lk_lock & ~(LK_FLAGMASK & ~LK_SHARE)) == (uintptr_t)curthread) static void assert_lockmgr(const struct lock_object *lock, int how); #ifdef DDB static void db_show_lockmgr(const struct lock_object *lock); #endif static void lock_lockmgr(struct lock_object *lock, int how); #ifdef KDTRACE_HOOKS static int owner_lockmgr(const struct lock_object *lock, struct thread **owner); #endif static int unlock_lockmgr(struct lock_object *lock); struct lock_class lock_class_lockmgr = { .lc_name = "lockmgr", .lc_flags = LC_RECURSABLE | LC_SLEEPABLE | LC_SLEEPLOCK | LC_UPGRADABLE, .lc_assert = assert_lockmgr, #ifdef DDB .lc_ddb_show = db_show_lockmgr, #endif .lc_lock = lock_lockmgr, .lc_unlock = unlock_lockmgr, #ifdef KDTRACE_HOOKS .lc_owner = owner_lockmgr, #endif }; #ifdef ADAPTIVE_LOCKMGRS static u_int alk_retries = 10; static u_int alk_loops = 10000; static SYSCTL_NODE(_debug, OID_AUTO, lockmgr, CTLFLAG_RD, NULL, "lockmgr debugging"); SYSCTL_UINT(_debug_lockmgr, OID_AUTO, retries, CTLFLAG_RW, &alk_retries, 0, ""); SYSCTL_UINT(_debug_lockmgr, OID_AUTO, loops, CTLFLAG_RW, &alk_loops, 0, ""); #endif static __inline struct thread * lockmgr_xholder(const struct lock *lk) { uintptr_t x; x = lk->lk_lock; return ((x & LK_SHARE) ? NULL : (struct thread *)LK_HOLDER(x)); } /* * It assumes sleepq_lock held and returns with this one unheld. * It also assumes the generic interlock is sane and previously checked. * If LK_INTERLOCK is specified the interlock is not reacquired after the * sleep. */ static __inline int sleeplk(struct lock *lk, u_int flags, struct lock_object *ilk, const char *wmesg, int pri, int timo, int queue) { GIANT_DECLARE; struct lock_class *class; int catch, error; class = (flags & LK_INTERLOCK) ? LOCK_CLASS(ilk) : NULL; catch = pri & PCATCH; pri &= PRIMASK; error = 0; LOCK_LOG3(lk, "%s: %p blocking on the %s sleepqueue", __func__, lk, (queue == SQ_EXCLUSIVE_QUEUE) ? "exclusive" : "shared"); if (flags & LK_INTERLOCK) class->lc_unlock(ilk); if (queue == SQ_EXCLUSIVE_QUEUE && (flags & LK_SLEEPFAIL) != 0) lk->lk_exslpfail++; GIANT_SAVE(); sleepq_add(&lk->lock_object, NULL, wmesg, SLEEPQ_LK | (catch ? SLEEPQ_INTERRUPTIBLE : 0), queue); if ((flags & LK_TIMELOCK) && timo) sleepq_set_timeout(&lk->lock_object, timo); /* * Decisional switch for real sleeping. */ if ((flags & LK_TIMELOCK) && timo && catch) error = sleepq_timedwait_sig(&lk->lock_object, pri); else if ((flags & LK_TIMELOCK) && timo) error = sleepq_timedwait(&lk->lock_object, pri); else if (catch) error = sleepq_wait_sig(&lk->lock_object, pri); else sleepq_wait(&lk->lock_object, pri); GIANT_RESTORE(); if ((flags & LK_SLEEPFAIL) && error == 0) error = ENOLCK; return (error); } static __inline int wakeupshlk(struct lock *lk, const char *file, int line) { uintptr_t v, x; u_int realexslp; int queue, wakeup_swapper; TD_LOCKS_DEC(curthread); TD_SLOCKS_DEC(curthread); WITNESS_UNLOCK(&lk->lock_object, 0, file, line); LOCK_LOG_LOCK("SUNLOCK", &lk->lock_object, 0, 0, file, line); wakeup_swapper = 0; for (;;) { x = lk->lk_lock; /* * If there is more than one shared lock held, just drop one * and return. */ if (LK_SHARERS(x) > 1) { if (atomic_cmpset_rel_ptr(&lk->lk_lock, x, x - LK_ONE_SHARER)) break; continue; } /* * If there are not waiters on the exclusive queue, drop the * lock quickly. */ if ((x & LK_ALL_WAITERS) == 0) { MPASS((x & ~LK_EXCLUSIVE_SPINNERS) == LK_SHARERS_LOCK(1)); if (atomic_cmpset_rel_ptr(&lk->lk_lock, x, LK_UNLOCKED)) break; continue; } /* * We should have a sharer with waiters, so enter the hard * path in order to handle wakeups correctly. */ sleepq_lock(&lk->lock_object); x = lk->lk_lock & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); v = LK_UNLOCKED; /* * If the lock has exclusive waiters, give them preference in * order to avoid deadlock with shared runners up. * If interruptible sleeps left the exclusive queue empty * avoid a starvation for the threads sleeping on the shared * queue by giving them precedence and cleaning up the * exclusive waiters bit anyway. * Please note that lk_exslpfail count may be lying about * the real number of waiters with the LK_SLEEPFAIL flag on * because they may be used in conjuction with interruptible * sleeps so lk_exslpfail might be considered an 'upper limit' * bound, including the edge cases. */ realexslp = sleepq_sleepcnt(&lk->lock_object, SQ_EXCLUSIVE_QUEUE); if ((x & LK_EXCLUSIVE_WAITERS) != 0 && realexslp != 0) { if (lk->lk_exslpfail < realexslp) { lk->lk_exslpfail = 0; queue = SQ_EXCLUSIVE_QUEUE; v |= (x & LK_SHARED_WAITERS); } else { lk->lk_exslpfail = 0; LOCK_LOG2(lk, "%s: %p has only LK_SLEEPFAIL sleepers", __func__, lk); LOCK_LOG2(lk, "%s: %p waking up threads on the exclusive queue", __func__, lk); wakeup_swapper = sleepq_broadcast(&lk->lock_object, SLEEPQ_LK, 0, SQ_EXCLUSIVE_QUEUE); queue = SQ_SHARED_QUEUE; } } else { /* * Exclusive waiters sleeping with LK_SLEEPFAIL on * and using interruptible sleeps/timeout may have * left spourious lk_exslpfail counts on, so clean * it up anyway. */ lk->lk_exslpfail = 0; queue = SQ_SHARED_QUEUE; } if (!atomic_cmpset_rel_ptr(&lk->lk_lock, LK_SHARERS_LOCK(1) | x, v)) { sleepq_release(&lk->lock_object); continue; } LOCK_LOG3(lk, "%s: %p waking up threads on the %s queue", __func__, lk, queue == SQ_SHARED_QUEUE ? "shared" : "exclusive"); wakeup_swapper |= sleepq_broadcast(&lk->lock_object, SLEEPQ_LK, 0, queue); sleepq_release(&lk->lock_object); break; } lock_profile_release_lock(&lk->lock_object); return (wakeup_swapper); } static void assert_lockmgr(const struct lock_object *lock, int what) { panic("lockmgr locks do not support assertions"); } static void lock_lockmgr(struct lock_object *lock, int how) { panic("lockmgr locks do not support sleep interlocking"); } static int unlock_lockmgr(struct lock_object *lock) { panic("lockmgr locks do not support sleep interlocking"); } #ifdef KDTRACE_HOOKS static int owner_lockmgr(const struct lock_object *lock, struct thread **owner) { panic("lockmgr locks do not support owner inquiring"); } #endif void lockinit(struct lock *lk, int pri, const char *wmesg, int timo, int flags) { int iflags; MPASS((flags & ~LK_INIT_MASK) == 0); ASSERT_ATOMIC_LOAD_PTR(lk->lk_lock, ("%s: lockmgr not aligned for %s: %p", __func__, wmesg, &lk->lk_lock)); iflags = LO_SLEEPABLE | LO_UPGRADABLE; if (flags & LK_CANRECURSE) iflags |= LO_RECURSABLE; if ((flags & LK_NODUP) == 0) iflags |= LO_DUPOK; if (flags & LK_NOPROFILE) iflags |= LO_NOPROFILE; if ((flags & LK_NOWITNESS) == 0) iflags |= LO_WITNESS; if (flags & LK_QUIET) iflags |= LO_QUIET; iflags |= flags & (LK_ADAPTIVE | LK_NOSHARE); lk->lk_lock = LK_UNLOCKED; lk->lk_recurse = 0; lk->lk_exslpfail = 0; lk->lk_timo = timo; lk->lk_pri = pri; lock_init(&lk->lock_object, &lock_class_lockmgr, wmesg, NULL, iflags); STACK_ZERO(lk); } /* * XXX: Gross hacks to manipulate external lock flags after * initialization. Used for certain vnode and buf locks. */ void lockallowshare(struct lock *lk) { lockmgr_assert(lk, KA_XLOCKED); lk->lock_object.lo_flags &= ~LK_NOSHARE; } void lockallowrecurse(struct lock *lk) { lockmgr_assert(lk, KA_XLOCKED); lk->lock_object.lo_flags |= LO_RECURSABLE; } void lockdisablerecurse(struct lock *lk) { lockmgr_assert(lk, KA_XLOCKED); lk->lock_object.lo_flags &= ~LO_RECURSABLE; } void lockdestroy(struct lock *lk) { KASSERT(lk->lk_lock == LK_UNLOCKED, ("lockmgr still held")); KASSERT(lk->lk_recurse == 0, ("lockmgr still recursed")); KASSERT(lk->lk_exslpfail == 0, ("lockmgr still exclusive waiters")); lock_destroy(&lk->lock_object); } int __lockmgr_args(struct lock *lk, u_int flags, struct lock_object *ilk, const char *wmesg, int pri, int timo, const char *file, int line) { GIANT_DECLARE; struct lock_class *class; const char *iwmesg; uintptr_t tid, v, x; u_int op, realexslp; int error, ipri, itimo, queue, wakeup_swapper; #ifdef LOCK_PROFILING uint64_t waittime = 0; int contested = 0; #endif #ifdef ADAPTIVE_LOCKMGRS volatile struct thread *owner; u_int i, spintries = 0; #endif error = 0; tid = (uintptr_t)curthread; op = (flags & LK_TYPE_MASK); iwmesg = (wmesg == LK_WMESG_DEFAULT) ? lk->lock_object.lo_name : wmesg; ipri = (pri == LK_PRIO_DEFAULT) ? lk->lk_pri : pri; itimo = (timo == LK_TIMO_DEFAULT) ? lk->lk_timo : timo; MPASS((flags & ~LK_TOTAL_MASK) == 0); KASSERT((op & (op - 1)) == 0, ("%s: Invalid requested operation @ %s:%d", __func__, file, line)); KASSERT((flags & (LK_NOWAIT | LK_SLEEPFAIL)) == 0 || (op != LK_DOWNGRADE && op != LK_RELEASE), ("%s: Invalid flags in regard of the operation desired @ %s:%d", __func__, file, line)); KASSERT((flags & LK_INTERLOCK) == 0 || ilk != NULL, ("%s: LK_INTERLOCK passed without valid interlock @ %s:%d", __func__, file, line)); class = (flags & LK_INTERLOCK) ? LOCK_CLASS(ilk) : NULL; if (panicstr != NULL) { if (flags & LK_INTERLOCK) class->lc_unlock(ilk); return (0); } if (lk->lock_object.lo_flags & LK_NOSHARE) { switch (op) { case LK_SHARED: op = LK_EXCLUSIVE; break; case LK_UPGRADE: case LK_DOWNGRADE: _lockmgr_assert(lk, KA_XLOCKED | KA_NOTRECURSED, file, line); return (0); } } wakeup_swapper = 0; switch (op) { case LK_SHARED: if (LK_CAN_WITNESS(flags)) WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER, file, line, ilk); for (;;) { x = lk->lk_lock; /* * If no other thread has an exclusive lock, or * no exclusive waiter is present, bump the count of * sharers. Since we have to preserve the state of * waiters, if we fail to acquire the shared lock * loop back and retry. */ if (LK_CAN_SHARE(x)) { if (atomic_cmpset_acq_ptr(&lk->lk_lock, x, x + LK_ONE_SHARER)) break; continue; } lock_profile_obtain_lock_failed(&lk->lock_object, &contested, &waittime); /* * If the lock is already held by curthread in * exclusive way avoid a deadlock. */ if (LK_HOLDER(x) == tid) { LOCK_LOG2(lk, "%s: %p already held in exclusive mode", __func__, lk); error = EDEADLK; break; } /* * If the lock is expected to not sleep just give up * and return. */ if (LK_TRYOP(flags)) { LOCK_LOG2(lk, "%s: %p fails the try operation", __func__, lk); error = EBUSY; break; } #ifdef ADAPTIVE_LOCKMGRS /* * If the owner is running on another CPU, spin until * the owner stops running or the state of the lock * changes. We need a double-state handle here * because for a failed acquisition the lock can be * either held in exclusive mode or shared mode * (for the writer starvation avoidance technique). */ if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && LK_HOLDER(x) != LK_KERNPROC) { owner = (struct thread *)LK_HOLDER(x); if (LOCK_LOG_TEST(&lk->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, lk, owner); /* * If we are holding also an interlock drop it * in order to avoid a deadlock if the lockmgr * owner is adaptively spinning on the * interlock itself. */ if (flags & LK_INTERLOCK) { class->lc_unlock(ilk); flags &= ~LK_INTERLOCK; } GIANT_SAVE(); while (LK_HOLDER(lk->lk_lock) == (uintptr_t)owner && TD_IS_RUNNING(owner)) cpu_spinwait(); GIANT_RESTORE(); continue; } else if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) != 0 && LK_SHARERS(x) && spintries < alk_retries) { if (flags & LK_INTERLOCK) { class->lc_unlock(ilk); flags &= ~LK_INTERLOCK; } GIANT_SAVE(); spintries++; for (i = 0; i < alk_loops; i++) { if (LOCK_LOG_TEST(&lk->lock_object, 0)) CTR4(KTR_LOCK, "%s: shared spinning on %p with %u and %u", __func__, lk, spintries, i); x = lk->lk_lock; if ((x & LK_SHARE) == 0 || LK_CAN_SHARE(x) != 0) break; cpu_spinwait(); } GIANT_RESTORE(); if (i != alk_loops) continue; } #endif /* * Acquire the sleepqueue chain lock because we * probabilly will need to manipulate waiters flags. */ sleepq_lock(&lk->lock_object); x = lk->lk_lock; /* * if the lock can be acquired in shared mode, try * again. */ if (LK_CAN_SHARE(x)) { sleepq_release(&lk->lock_object); continue; } #ifdef ADAPTIVE_LOCKMGRS /* * The current lock owner might have started executing * on another CPU (or the lock could have changed * owner) while we were waiting on the turnstile * chain lock. If so, drop the turnstile lock and try * again. */ if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && LK_HOLDER(x) != LK_KERNPROC) { owner = (struct thread *)LK_HOLDER(x); if (TD_IS_RUNNING(owner)) { sleepq_release(&lk->lock_object); continue; } } #endif /* * Try to set the LK_SHARED_WAITERS flag. If we fail, * loop back and retry. */ if ((x & LK_SHARED_WAITERS) == 0) { if (!atomic_cmpset_acq_ptr(&lk->lk_lock, x, x | LK_SHARED_WAITERS)) { sleepq_release(&lk->lock_object); continue; } LOCK_LOG2(lk, "%s: %p set shared waiters flag", __func__, lk); } /* * As far as we have been unable to acquire the * shared lock and the shared waiters flag is set, * we will sleep. */ error = sleeplk(lk, flags, ilk, iwmesg, ipri, itimo, SQ_SHARED_QUEUE); flags &= ~LK_INTERLOCK; if (error) { LOCK_LOG3(lk, "%s: interrupted sleep for %p with %d", __func__, lk, error); break; } LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", __func__, lk); } if (error == 0) { lock_profile_obtain_lock_success(&lk->lock_object, contested, waittime, file, line); LOCK_LOG_LOCK("SLOCK", &lk->lock_object, 0, 0, file, line); WITNESS_LOCK(&lk->lock_object, LK_TRYWIT(flags), file, line); TD_LOCKS_INC(curthread); TD_SLOCKS_INC(curthread); STACK_SAVE(lk); } break; case LK_UPGRADE: _lockmgr_assert(lk, KA_SLOCKED, file, line); v = lk->lk_lock; x = v & LK_ALL_WAITERS; v &= LK_EXCLUSIVE_SPINNERS; /* * Try to switch from one shared lock to an exclusive one. * We need to preserve waiters flags during the operation. */ if (atomic_cmpset_ptr(&lk->lk_lock, LK_SHARERS_LOCK(1) | x | v, tid | x)) { LOCK_LOG_LOCK("XUPGRADE", &lk->lock_object, 0, 0, file, line); WITNESS_UPGRADE(&lk->lock_object, LOP_EXCLUSIVE | LK_TRYWIT(flags), file, line); TD_SLOCKS_DEC(curthread); break; } /* * We have been unable to succeed in upgrading, so just * give up the shared lock. */ wakeup_swapper |= wakeupshlk(lk, file, line); /* FALLTHROUGH */ case LK_EXCLUSIVE: if (LK_CAN_WITNESS(flags)) WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER | LOP_EXCLUSIVE, file, line, ilk); /* * If curthread already holds the lock and this one is * allowed to recurse, simply recurse on it. */ if (lockmgr_xlocked(lk)) { if ((flags & LK_CANRECURSE) == 0 && (lk->lock_object.lo_flags & LO_RECURSABLE) == 0) { /* * If the lock is expected to not panic just * give up and return. */ if (LK_TRYOP(flags)) { LOCK_LOG2(lk, "%s: %p fails the try operation", __func__, lk); error = EBUSY; break; } if (flags & LK_INTERLOCK) class->lc_unlock(ilk); panic("%s: recursing on non recursive lockmgr %s @ %s:%d\n", __func__, iwmesg, file, line); } lk->lk_recurse++; LOCK_LOG2(lk, "%s: %p recursing", __func__, lk); LOCK_LOG_LOCK("XLOCK", &lk->lock_object, 0, lk->lk_recurse, file, line); WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | LK_TRYWIT(flags), file, line); TD_LOCKS_INC(curthread); break; } while (!atomic_cmpset_acq_ptr(&lk->lk_lock, LK_UNLOCKED, tid)) { lock_profile_obtain_lock_failed(&lk->lock_object, &contested, &waittime); /* * If the lock is expected to not sleep just give up * and return. */ if (LK_TRYOP(flags)) { LOCK_LOG2(lk, "%s: %p fails the try operation", __func__, lk); error = EBUSY; break; } #ifdef ADAPTIVE_LOCKMGRS /* * If the owner is running on another CPU, spin until * the owner stops running or the state of the lock * changes. */ x = lk->lk_lock; if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && LK_HOLDER(x) != LK_KERNPROC) { owner = (struct thread *)LK_HOLDER(x); if (LOCK_LOG_TEST(&lk->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, lk, owner); /* * If we are holding also an interlock drop it * in order to avoid a deadlock if the lockmgr * owner is adaptively spinning on the * interlock itself. */ if (flags & LK_INTERLOCK) { class->lc_unlock(ilk); flags &= ~LK_INTERLOCK; } GIANT_SAVE(); while (LK_HOLDER(lk->lk_lock) == (uintptr_t)owner && TD_IS_RUNNING(owner)) cpu_spinwait(); GIANT_RESTORE(); continue; } else if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) != 0 && LK_SHARERS(x) && spintries < alk_retries) { if ((x & LK_EXCLUSIVE_SPINNERS) == 0 && !atomic_cmpset_ptr(&lk->lk_lock, x, x | LK_EXCLUSIVE_SPINNERS)) continue; if (flags & LK_INTERLOCK) { class->lc_unlock(ilk); flags &= ~LK_INTERLOCK; } GIANT_SAVE(); spintries++; for (i = 0; i < alk_loops; i++) { if (LOCK_LOG_TEST(&lk->lock_object, 0)) CTR4(KTR_LOCK, "%s: shared spinning on %p with %u and %u", __func__, lk, spintries, i); if ((lk->lk_lock & LK_EXCLUSIVE_SPINNERS) == 0) break; cpu_spinwait(); } GIANT_RESTORE(); if (i != alk_loops) continue; } #endif /* * Acquire the sleepqueue chain lock because we * probabilly will need to manipulate waiters flags. */ sleepq_lock(&lk->lock_object); x = lk->lk_lock; /* * if the lock has been released while we spun on * the sleepqueue chain lock just try again. */ if (x == LK_UNLOCKED) { sleepq_release(&lk->lock_object); continue; } #ifdef ADAPTIVE_LOCKMGRS /* * The current lock owner might have started executing * on another CPU (or the lock could have changed * owner) while we were waiting on the turnstile * chain lock. If so, drop the turnstile lock and try * again. */ if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && LK_HOLDER(x) != LK_KERNPROC) { owner = (struct thread *)LK_HOLDER(x); if (TD_IS_RUNNING(owner)) { sleepq_release(&lk->lock_object); continue; } } #endif /* * The lock can be in the state where there is a * pending queue of waiters, but still no owner. * This happens when the lock is contested and an * owner is going to claim the lock. * If curthread is the one successfully acquiring it * claim lock ownership and return, preserving waiters * flags. */ v = x & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); if ((x & ~v) == LK_UNLOCKED) { v &= ~LK_EXCLUSIVE_SPINNERS; if (atomic_cmpset_acq_ptr(&lk->lk_lock, x, tid | v)) { sleepq_release(&lk->lock_object); LOCK_LOG2(lk, "%s: %p claimed by a new writer", __func__, lk); break; } sleepq_release(&lk->lock_object); continue; } /* * Try to set the LK_EXCLUSIVE_WAITERS flag. If we * fail, loop back and retry. */ if ((x & LK_EXCLUSIVE_WAITERS) == 0) { if (!atomic_cmpset_ptr(&lk->lk_lock, x, x | LK_EXCLUSIVE_WAITERS)) { sleepq_release(&lk->lock_object); continue; } LOCK_LOG2(lk, "%s: %p set excl waiters flag", __func__, lk); } /* * As far as we have been unable to acquire the * exclusive lock and the exclusive waiters flag * is set, we will sleep. */ error = sleeplk(lk, flags, ilk, iwmesg, ipri, itimo, SQ_EXCLUSIVE_QUEUE); flags &= ~LK_INTERLOCK; if (error) { LOCK_LOG3(lk, "%s: interrupted sleep for %p with %d", __func__, lk, error); break; } LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", __func__, lk); } if (error == 0) { lock_profile_obtain_lock_success(&lk->lock_object, contested, waittime, file, line); LOCK_LOG_LOCK("XLOCK", &lk->lock_object, 0, lk->lk_recurse, file, line); WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | LK_TRYWIT(flags), file, line); TD_LOCKS_INC(curthread); STACK_SAVE(lk); } break; case LK_DOWNGRADE: _lockmgr_assert(lk, KA_XLOCKED | KA_NOTRECURSED, file, line); LOCK_LOG_LOCK("XDOWNGRADE", &lk->lock_object, 0, 0, file, line); WITNESS_DOWNGRADE(&lk->lock_object, 0, file, line); TD_SLOCKS_INC(curthread); /* * In order to preserve waiters flags, just spin. */ for (;;) { x = lk->lk_lock; MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); x &= LK_ALL_WAITERS; if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid | x, LK_SHARERS_LOCK(1) | x)) break; cpu_spinwait(); } break; case LK_RELEASE: _lockmgr_assert(lk, KA_LOCKED, file, line); x = lk->lk_lock; if ((x & LK_SHARE) == 0) { /* * As first option, treact the lock as if it has not * any waiter. * Fix-up the tid var if the lock has been disowned. */ if (LK_HOLDER(x) == LK_KERNPROC) tid = LK_KERNPROC; else { WITNESS_UNLOCK(&lk->lock_object, LOP_EXCLUSIVE, file, line); TD_LOCKS_DEC(curthread); } LOCK_LOG_LOCK("XUNLOCK", &lk->lock_object, 0, lk->lk_recurse, file, line); /* * The lock is held in exclusive mode. * If the lock is recursed also, then unrecurse it. */ if (lockmgr_xlocked(lk) && lockmgr_recursed(lk)) { LOCK_LOG2(lk, "%s: %p unrecursing", __func__, lk); lk->lk_recurse--; break; } if (tid != LK_KERNPROC) lock_profile_release_lock(&lk->lock_object); if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid, LK_UNLOCKED)) break; sleepq_lock(&lk->lock_object); x = lk->lk_lock; v = LK_UNLOCKED; /* * If the lock has exclusive waiters, give them * preference in order to avoid deadlock with * shared runners up. * If interruptible sleeps left the exclusive queue * empty avoid a starvation for the threads sleeping * on the shared queue by giving them precedence * and cleaning up the exclusive waiters bit anyway. * Please note that lk_exslpfail count may be lying * about the real number of waiters with the * LK_SLEEPFAIL flag on because they may be used in * conjuction with interruptible sleeps so * lk_exslpfail might be considered an 'upper limit' * bound, including the edge cases. */ MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); realexslp = sleepq_sleepcnt(&lk->lock_object, SQ_EXCLUSIVE_QUEUE); if ((x & LK_EXCLUSIVE_WAITERS) != 0 && realexslp != 0) { if (lk->lk_exslpfail < realexslp) { lk->lk_exslpfail = 0; queue = SQ_EXCLUSIVE_QUEUE; v |= (x & LK_SHARED_WAITERS); } else { lk->lk_exslpfail = 0; LOCK_LOG2(lk, "%s: %p has only LK_SLEEPFAIL sleepers", __func__, lk); LOCK_LOG2(lk, "%s: %p waking up threads on the exclusive queue", __func__, lk); wakeup_swapper = sleepq_broadcast(&lk->lock_object, SLEEPQ_LK, 0, SQ_EXCLUSIVE_QUEUE); queue = SQ_SHARED_QUEUE; } } else { /* * Exclusive waiters sleeping with LK_SLEEPFAIL * on and using interruptible sleeps/timeout * may have left spourious lk_exslpfail counts * on, so clean it up anyway. */ lk->lk_exslpfail = 0; queue = SQ_SHARED_QUEUE; } LOCK_LOG3(lk, "%s: %p waking up threads on the %s queue", __func__, lk, queue == SQ_SHARED_QUEUE ? "shared" : "exclusive"); atomic_store_rel_ptr(&lk->lk_lock, v); wakeup_swapper |= sleepq_broadcast(&lk->lock_object, SLEEPQ_LK, 0, queue); sleepq_release(&lk->lock_object); break; } else wakeup_swapper = wakeupshlk(lk, file, line); break; case LK_DRAIN: if (LK_CAN_WITNESS(flags)) WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER | LOP_EXCLUSIVE, file, line, ilk); /* * Trying to drain a lock we already own will result in a * deadlock. */ if (lockmgr_xlocked(lk)) { if (flags & LK_INTERLOCK) class->lc_unlock(ilk); panic("%s: draining %s with the lock held @ %s:%d\n", __func__, iwmesg, file, line); } while (!atomic_cmpset_acq_ptr(&lk->lk_lock, LK_UNLOCKED, tid)) { lock_profile_obtain_lock_failed(&lk->lock_object, &contested, &waittime); /* * If the lock is expected to not sleep just give up * and return. */ if (LK_TRYOP(flags)) { LOCK_LOG2(lk, "%s: %p fails the try operation", __func__, lk); error = EBUSY; break; } /* * Acquire the sleepqueue chain lock because we * probabilly will need to manipulate waiters flags. */ sleepq_lock(&lk->lock_object); x = lk->lk_lock; /* * if the lock has been released while we spun on * the sleepqueue chain lock just try again. */ if (x == LK_UNLOCKED) { sleepq_release(&lk->lock_object); continue; } v = x & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); if ((x & ~v) == LK_UNLOCKED) { v = (x & ~LK_EXCLUSIVE_SPINNERS); /* * If interruptible sleeps left the exclusive * queue empty avoid a starvation for the * threads sleeping on the shared queue by * giving them precedence and cleaning up the * exclusive waiters bit anyway. * Please note that lk_exslpfail count may be * lying about the real number of waiters with * the LK_SLEEPFAIL flag on because they may * be used in conjuction with interruptible * sleeps so lk_exslpfail might be considered * an 'upper limit' bound, including the edge * cases. */ if (v & LK_EXCLUSIVE_WAITERS) { queue = SQ_EXCLUSIVE_QUEUE; v &= ~LK_EXCLUSIVE_WAITERS; } else { /* * Exclusive waiters sleeping with * LK_SLEEPFAIL on and using * interruptible sleeps/timeout may * have left spourious lk_exslpfail * counts on, so clean it up anyway. */ MPASS(v & LK_SHARED_WAITERS); lk->lk_exslpfail = 0; queue = SQ_SHARED_QUEUE; v &= ~LK_SHARED_WAITERS; } if (queue == SQ_EXCLUSIVE_QUEUE) { realexslp = sleepq_sleepcnt(&lk->lock_object, SQ_EXCLUSIVE_QUEUE); if (lk->lk_exslpfail >= realexslp) { lk->lk_exslpfail = 0; queue = SQ_SHARED_QUEUE; v &= ~LK_SHARED_WAITERS; if (realexslp != 0) { LOCK_LOG2(lk, "%s: %p has only LK_SLEEPFAIL sleepers", __func__, lk); LOCK_LOG2(lk, "%s: %p waking up threads on the exclusive queue", __func__, lk); wakeup_swapper = sleepq_broadcast( &lk->lock_object, SLEEPQ_LK, 0, SQ_EXCLUSIVE_QUEUE); } } else lk->lk_exslpfail = 0; } if (!atomic_cmpset_ptr(&lk->lk_lock, x, v)) { sleepq_release(&lk->lock_object); continue; } LOCK_LOG3(lk, "%s: %p waking up all threads on the %s queue", __func__, lk, queue == SQ_SHARED_QUEUE ? "shared" : "exclusive"); wakeup_swapper |= sleepq_broadcast( &lk->lock_object, SLEEPQ_LK, 0, queue); /* * If shared waiters have been woken up we need * to wait for one of them to acquire the lock * before to set the exclusive waiters in * order to avoid a deadlock. */ if (queue == SQ_SHARED_QUEUE) { for (v = lk->lk_lock; (v & LK_SHARE) && !LK_SHARERS(v); v = lk->lk_lock) cpu_spinwait(); } } /* * Try to set the LK_EXCLUSIVE_WAITERS flag. If we * fail, loop back and retry. */ if ((x & LK_EXCLUSIVE_WAITERS) == 0) { if (!atomic_cmpset_ptr(&lk->lk_lock, x, x | LK_EXCLUSIVE_WAITERS)) { sleepq_release(&lk->lock_object); continue; } LOCK_LOG2(lk, "%s: %p set drain waiters flag", __func__, lk); } /* * As far as we have been unable to acquire the * exclusive lock and the exclusive waiters flag * is set, we will sleep. */ if (flags & LK_INTERLOCK) { class->lc_unlock(ilk); flags &= ~LK_INTERLOCK; } GIANT_SAVE(); sleepq_add(&lk->lock_object, NULL, iwmesg, SLEEPQ_LK, SQ_EXCLUSIVE_QUEUE); sleepq_wait(&lk->lock_object, ipri & PRIMASK); GIANT_RESTORE(); LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", __func__, lk); } if (error == 0) { lock_profile_obtain_lock_success(&lk->lock_object, contested, waittime, file, line); LOCK_LOG_LOCK("DRAIN", &lk->lock_object, 0, lk->lk_recurse, file, line); WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | LK_TRYWIT(flags), file, line); TD_LOCKS_INC(curthread); STACK_SAVE(lk); } break; default: if (flags & LK_INTERLOCK) class->lc_unlock(ilk); panic("%s: unknown lockmgr request 0x%x\n", __func__, op); } if (flags & LK_INTERLOCK) class->lc_unlock(ilk); if (wakeup_swapper) kick_proc0(); return (error); } void _lockmgr_disown(struct lock *lk, const char *file, int line) { uintptr_t tid, x; + if (SCHEDULER_STOPPED()) + return; + tid = (uintptr_t)curthread; _lockmgr_assert(lk, KA_XLOCKED | KA_NOTRECURSED, file, line); /* * If the owner is already LK_KERNPROC just skip the whole operation. */ if (LK_HOLDER(lk->lk_lock) != tid) return; lock_profile_release_lock(&lk->lock_object); LOCK_LOG_LOCK("XDISOWN", &lk->lock_object, 0, 0, file, line); WITNESS_UNLOCK(&lk->lock_object, LOP_EXCLUSIVE, file, line); TD_LOCKS_DEC(curthread); STACK_SAVE(lk); /* * In order to preserve waiters flags, just spin. */ for (;;) { x = lk->lk_lock; MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); x &= LK_ALL_WAITERS; if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid | x, LK_KERNPROC | x)) return; cpu_spinwait(); } } void lockmgr_printinfo(const struct lock *lk) { struct thread *td; uintptr_t x; if (lk->lk_lock == LK_UNLOCKED) printf("lock type %s: UNLOCKED\n", lk->lock_object.lo_name); else if (lk->lk_lock & LK_SHARE) printf("lock type %s: SHARED (count %ju)\n", lk->lock_object.lo_name, (uintmax_t)LK_SHARERS(lk->lk_lock)); else { td = lockmgr_xholder(lk); printf("lock type %s: EXCL by thread %p (pid %d)\n", lk->lock_object.lo_name, td, td->td_proc->p_pid); } x = lk->lk_lock; if (x & LK_EXCLUSIVE_WAITERS) printf(" with exclusive waiters pending\n"); if (x & LK_SHARED_WAITERS) printf(" with shared waiters pending\n"); if (x & LK_EXCLUSIVE_SPINNERS) printf(" with exclusive spinners pending\n"); STACK_PRINT(lk); } int lockstatus(const struct lock *lk) { uintptr_t v, x; int ret; ret = LK_SHARED; x = lk->lk_lock; v = LK_HOLDER(x); if ((x & LK_SHARE) == 0) { if (v == (uintptr_t)curthread || v == LK_KERNPROC) ret = LK_EXCLUSIVE; else ret = LK_EXCLOTHER; } else if (x == LK_UNLOCKED) ret = 0; return (ret); } #ifdef INVARIANT_SUPPORT FEATURE(invariant_support, "Support for modules compiled with INVARIANTS option"); #ifndef INVARIANTS #undef _lockmgr_assert #endif void _lockmgr_assert(const struct lock *lk, int what, const char *file, int line) { int slocked = 0; if (panicstr != NULL) return; switch (what) { case KA_SLOCKED: case KA_SLOCKED | KA_NOTRECURSED: case KA_SLOCKED | KA_RECURSED: slocked = 1; case KA_LOCKED: case KA_LOCKED | KA_NOTRECURSED: case KA_LOCKED | KA_RECURSED: #ifdef WITNESS /* * We cannot trust WITNESS if the lock is held in exclusive * mode and a call to lockmgr_disown() happened. * Workaround this skipping the check if the lock is held in * exclusive mode even for the KA_LOCKED case. */ if (slocked || (lk->lk_lock & LK_SHARE)) { witness_assert(&lk->lock_object, what, file, line); break; } #endif if (lk->lk_lock == LK_UNLOCKED || ((lk->lk_lock & LK_SHARE) == 0 && (slocked || (!lockmgr_xlocked(lk) && !lockmgr_disowned(lk))))) panic("Lock %s not %slocked @ %s:%d\n", lk->lock_object.lo_name, slocked ? "share" : "", file, line); if ((lk->lk_lock & LK_SHARE) == 0) { if (lockmgr_recursed(lk)) { if (what & KA_NOTRECURSED) panic("Lock %s recursed @ %s:%d\n", lk->lock_object.lo_name, file, line); } else if (what & KA_RECURSED) panic("Lock %s not recursed @ %s:%d\n", lk->lock_object.lo_name, file, line); } break; case KA_XLOCKED: case KA_XLOCKED | KA_NOTRECURSED: case KA_XLOCKED | KA_RECURSED: if (!lockmgr_xlocked(lk) && !lockmgr_disowned(lk)) panic("Lock %s not exclusively locked @ %s:%d\n", lk->lock_object.lo_name, file, line); if (lockmgr_recursed(lk)) { if (what & KA_NOTRECURSED) panic("Lock %s recursed @ %s:%d\n", lk->lock_object.lo_name, file, line); } else if (what & KA_RECURSED) panic("Lock %s not recursed @ %s:%d\n", lk->lock_object.lo_name, file, line); break; case KA_UNLOCKED: if (lockmgr_xlocked(lk) || lockmgr_disowned(lk)) panic("Lock %s exclusively locked @ %s:%d\n", lk->lock_object.lo_name, file, line); break; default: panic("Unknown lockmgr assertion: %d @ %s:%d\n", what, file, line); } } #endif #ifdef DDB int lockmgr_chain(struct thread *td, struct thread **ownerp) { struct lock *lk; lk = td->td_wchan; if (LOCK_CLASS(&lk->lock_object) != &lock_class_lockmgr) return (0); db_printf("blocked on lockmgr %s", lk->lock_object.lo_name); if (lk->lk_lock & LK_SHARE) db_printf("SHARED (count %ju)\n", (uintmax_t)LK_SHARERS(lk->lk_lock)); else db_printf("EXCL\n"); *ownerp = lockmgr_xholder(lk); return (1); } static void db_show_lockmgr(const struct lock_object *lock) { struct thread *td; const struct lock *lk; lk = (const struct lock *)lock; db_printf(" state: "); if (lk->lk_lock == LK_UNLOCKED) db_printf("UNLOCKED\n"); else if (lk->lk_lock & LK_SHARE) db_printf("SLOCK: %ju\n", (uintmax_t)LK_SHARERS(lk->lk_lock)); else { td = lockmgr_xholder(lk); if (td == (struct thread *)LK_KERNPROC) db_printf("XLOCK: LK_KERNPROC\n"); else db_printf("XLOCK: %p (tid %d, pid %d, \"%s\")\n", td, td->td_tid, td->td_proc->p_pid, td->td_proc->p_comm); if (lockmgr_recursed(lk)) db_printf(" recursed: %d\n", lk->lk_recurse); } db_printf(" waiters: "); switch (lk->lk_lock & LK_ALL_WAITERS) { case LK_SHARED_WAITERS: db_printf("shared\n"); break; case LK_EXCLUSIVE_WAITERS: db_printf("exclusive\n"); break; case LK_ALL_WAITERS: db_printf("shared and exclusive\n"); break; default: db_printf("none\n"); } db_printf(" spinners: "); if (lk->lk_lock & LK_EXCLUSIVE_SPINNERS) db_printf("exclusive\n"); else db_printf("none\n"); } #endif Index: head/sys/kern/kern_mutex.c =================================================================== --- head/sys/kern/kern_mutex.c (revision 228423) +++ head/sys/kern/kern_mutex.c (revision 228424) @@ -1,913 +1,938 @@ /*- * Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Berkeley Software Design Inc's name may not be used to endorse or * promote products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $ * and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $ */ /* * Machine independent bits of mutex implementation. */ #include __FBSDID("$FreeBSD$"); #include "opt_adaptive_mutexes.h" #include "opt_ddb.h" #include "opt_global.h" #include "opt_kdtrace.h" #include "opt_sched.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES) #define ADAPTIVE_MUTEXES #endif /* * Internal utility macros. */ #define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED) #define mtx_destroyed(m) ((m)->mtx_lock == MTX_DESTROYED) #define mtx_owner(m) ((struct thread *)((m)->mtx_lock & ~MTX_FLAGMASK)) static void assert_mtx(const struct lock_object *lock, int what); #ifdef DDB static void db_show_mtx(const struct lock_object *lock); #endif static void lock_mtx(struct lock_object *lock, int how); static void lock_spin(struct lock_object *lock, int how); #ifdef KDTRACE_HOOKS static int owner_mtx(const struct lock_object *lock, struct thread **owner); #endif static int unlock_mtx(struct lock_object *lock); static int unlock_spin(struct lock_object *lock); /* * Lock classes for sleep and spin mutexes. */ struct lock_class lock_class_mtx_sleep = { .lc_name = "sleep mutex", .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE, .lc_assert = assert_mtx, #ifdef DDB .lc_ddb_show = db_show_mtx, #endif .lc_lock = lock_mtx, .lc_unlock = unlock_mtx, #ifdef KDTRACE_HOOKS .lc_owner = owner_mtx, #endif }; struct lock_class lock_class_mtx_spin = { .lc_name = "spin mutex", .lc_flags = LC_SPINLOCK | LC_RECURSABLE, .lc_assert = assert_mtx, #ifdef DDB .lc_ddb_show = db_show_mtx, #endif .lc_lock = lock_spin, .lc_unlock = unlock_spin, #ifdef KDTRACE_HOOKS .lc_owner = owner_mtx, #endif }; /* * System-wide mutexes */ struct mtx blocked_lock; struct mtx Giant; void assert_mtx(const struct lock_object *lock, int what) { mtx_assert((const struct mtx *)lock, what); } void lock_mtx(struct lock_object *lock, int how) { mtx_lock((struct mtx *)lock); } void lock_spin(struct lock_object *lock, int how) { panic("spin locks can only use msleep_spin"); } int unlock_mtx(struct lock_object *lock) { struct mtx *m; m = (struct mtx *)lock; mtx_assert(m, MA_OWNED | MA_NOTRECURSED); mtx_unlock(m); return (0); } int unlock_spin(struct lock_object *lock) { panic("spin locks can only use msleep_spin"); } #ifdef KDTRACE_HOOKS int owner_mtx(const struct lock_object *lock, struct thread **owner) { const struct mtx *m = (const struct mtx *)lock; *owner = mtx_owner(m); return (mtx_unowned(m) == 0); } #endif /* * Function versions of the inlined __mtx_* macros. These are used by * modules and can also be called from assembly language if needed. */ void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line) { + if (SCHEDULER_STOPPED()) + return; MPASS(curthread != NULL); KASSERT(m->mtx_lock != MTX_DESTROYED, ("mtx_lock() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, ("mtx_lock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); __mtx_lock(m, curthread, opts, file, line); LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, line); WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); curthread->td_locks++; } void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line) { + + if (SCHEDULER_STOPPED()) + return; MPASS(curthread != NULL); KASSERT(m->mtx_lock != MTX_DESTROYED, ("mtx_unlock() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, ("mtx_unlock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); curthread->td_locks--; WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file, line); mtx_assert(m, MA_OWNED); if (m->mtx_recurse == 0) LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_UNLOCK_RELEASE, m); __mtx_unlock(m, curthread, opts, file, line); } void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, int line) { + if (SCHEDULER_STOPPED()) + return; MPASS(curthread != NULL); KASSERT(m->mtx_lock != MTX_DESTROYED, ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, ("mtx_lock_spin() of sleep mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); if (mtx_owned(m)) KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0, ("mtx_lock_spin: recursed on non-recursive mutex %s @ %s:%d\n", m->lock_object.lo_name, file, line)); WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); __mtx_lock_spin(m, curthread, opts, file, line); LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, line); WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); } void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, int line) { + if (SCHEDULER_STOPPED()) + return; MPASS(curthread != NULL); KASSERT(m->mtx_lock != MTX_DESTROYED, ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, ("mtx_unlock_spin() of sleep mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file, line); mtx_assert(m, MA_OWNED); __mtx_unlock_spin(m); } /* * The important part of mtx_trylock{,_flags}() * Tries to acquire lock `m.' If this function is called on a mutex that * is already owned, it will recursively acquire the lock. */ int mtx_trylock_flags_(struct mtx *m, int opts, const char *file, int line) { #ifdef LOCK_PROFILING uint64_t waittime = 0; int contested = 0; #endif int rval; + if (SCHEDULER_STOPPED()) + return (1); + MPASS(curthread != NULL); KASSERT(m->mtx_lock != MTX_DESTROYED, ("mtx_trylock() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, ("mtx_trylock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); if (mtx_owned(m) && (m->lock_object.lo_flags & LO_RECURSABLE) != 0) { m->mtx_recurse++; atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); rval = 1; } else rval = _mtx_obtain_lock(m, (uintptr_t)curthread); LOCK_LOG_TRY("LOCK", &m->lock_object, opts, rval, file, line); if (rval) { WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK, file, line); curthread->td_locks++; if (m->mtx_recurse == 0) LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE, m, contested, waittime, file, line); } return (rval); } /* * _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock. * * We call this if the lock is either contested (i.e. we need to go to * sleep waiting for it), or if we need to recurse on it. */ void _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, const char *file, int line) { struct turnstile *ts; uintptr_t v; #ifdef ADAPTIVE_MUTEXES volatile struct thread *owner; #endif #ifdef KTR int cont_logged = 0; #endif #ifdef LOCK_PROFILING int contested = 0; uint64_t waittime = 0; #endif #ifdef KDTRACE_HOOKS uint64_t spin_cnt = 0; uint64_t sleep_cnt = 0; int64_t sleep_time = 0; #endif + if (SCHEDULER_STOPPED()) + return; + if (mtx_owned(m)) { KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0, ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n", m->lock_object.lo_name, file, line)); m->mtx_recurse++; atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m); return; } lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime); if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR4(KTR_LOCK, "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d", m->lock_object.lo_name, (void *)m->mtx_lock, file, line); while (!_mtx_obtain_lock(m, tid)) { #ifdef KDTRACE_HOOKS spin_cnt++; #endif #ifdef ADAPTIVE_MUTEXES /* * If the owner is running on another CPU, spin until the * owner stops running or the state of the lock changes. */ v = m->mtx_lock; if (v != MTX_UNOWNED) { owner = (struct thread *)(v & ~MTX_FLAGMASK); if (TD_IS_RUNNING(owner)) { if (LOCK_LOG_TEST(&m->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, m, owner); while (mtx_owner(m) == owner && TD_IS_RUNNING(owner)) { cpu_spinwait(); #ifdef KDTRACE_HOOKS spin_cnt++; #endif } continue; } } #endif ts = turnstile_trywait(&m->lock_object); v = m->mtx_lock; /* * Check if the lock has been released while spinning for * the turnstile chain lock. */ if (v == MTX_UNOWNED) { turnstile_cancel(ts); continue; } #ifdef ADAPTIVE_MUTEXES /* * The current lock owner might have started executing * on another CPU (or the lock could have changed * owners) while we were waiting on the turnstile * chain lock. If so, drop the turnstile lock and try * again. */ owner = (struct thread *)(v & ~MTX_FLAGMASK); if (TD_IS_RUNNING(owner)) { turnstile_cancel(ts); continue; } #endif /* * If the mutex isn't already contested and a failure occurs * setting the contested bit, the mutex was either released * or the state of the MTX_RECURSED bit changed. */ if ((v & MTX_CONTESTED) == 0 && !atomic_cmpset_ptr(&m->mtx_lock, v, v | MTX_CONTESTED)) { turnstile_cancel(ts); continue; } /* * We definitely must sleep for this lock. */ mtx_assert(m, MA_NOTOWNED); #ifdef KTR if (!cont_logged) { CTR6(KTR_CONTENTION, "contention: %p at %s:%d wants %s, taken by %s:%d", (void *)tid, file, line, m->lock_object.lo_name, WITNESS_FILE(&m->lock_object), WITNESS_LINE(&m->lock_object)); cont_logged = 1; } #endif /* * Block on the turnstile. */ #ifdef KDTRACE_HOOKS sleep_time -= lockstat_nsecs(); #endif turnstile_wait(ts, mtx_owner(m), TS_EXCLUSIVE_QUEUE); #ifdef KDTRACE_HOOKS sleep_time += lockstat_nsecs(); sleep_cnt++; #endif } #ifdef KTR if (cont_logged) { CTR4(KTR_CONTENTION, "contention end: %s acquired by %p at %s:%d", m->lock_object.lo_name, (void *)tid, file, line); } #endif LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE, m, contested, waittime, file, line); #ifdef KDTRACE_HOOKS if (sleep_time) LOCKSTAT_RECORD1(LS_MTX_LOCK_BLOCK, m, sleep_time); /* * Only record the loops spinning and not sleeping. */ if (spin_cnt > sleep_cnt) LOCKSTAT_RECORD1(LS_MTX_LOCK_SPIN, m, (spin_cnt - sleep_cnt)); #endif } static void _mtx_lock_spin_failed(struct mtx *m) { struct thread *td; td = mtx_owner(m); /* If the mutex is unlocked, try again. */ if (td == NULL) return; printf( "spin lock %p (%s) held by %p (tid %d) too long\n", m, m->lock_object.lo_name, td, td->td_tid); #ifdef WITNESS witness_display_spinlock(&m->lock_object, td, printf); #endif panic("spin lock held too long"); } #ifdef SMP /* * _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock. * * This is only called if we need to actually spin for the lock. Recursion * is handled inline. */ void _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts, const char *file, int line) { int i = 0; #ifdef LOCK_PROFILING int contested = 0; uint64_t waittime = 0; #endif + if (SCHEDULER_STOPPED()) + return; + if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m); lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime); while (!_mtx_obtain_lock(m, tid)) { /* Give interrupts a chance while we spin. */ spinlock_exit(); while (m->mtx_lock != MTX_UNOWNED) { if (i++ < 10000000) { cpu_spinwait(); continue; } if (i < 60000000 || kdb_active || panicstr != NULL) DELAY(1); else _mtx_lock_spin_failed(m); cpu_spinwait(); } spinlock_enter(); } if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m); LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, m, contested, waittime, (file), (line)); LOCKSTAT_RECORD1(LS_MTX_SPIN_LOCK_SPIN, m, i); } #endif /* SMP */ void thread_lock_flags_(struct thread *td, int opts, const char *file, int line) { struct mtx *m; uintptr_t tid; int i; #ifdef LOCK_PROFILING int contested = 0; uint64_t waittime = 0; #endif #ifdef KDTRACE_HOOKS uint64_t spin_cnt = 0; #endif i = 0; tid = (uintptr_t)curthread; + + if (SCHEDULER_STOPPED()) + return; + for (;;) { retry: spinlock_enter(); m = td->td_lock; KASSERT(m->mtx_lock != MTX_DESTROYED, ("thread_lock() of destroyed mutex @ %s:%d", file, line)); KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, ("thread_lock() of sleep mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); if (mtx_owned(m)) KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0, ("thread_lock: recursed on non-recursive mutex %s @ %s:%d\n", m->lock_object.lo_name, file, line)); WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); while (!_mtx_obtain_lock(m, tid)) { #ifdef KDTRACE_HOOKS spin_cnt++; #endif if (m->mtx_lock == tid) { m->mtx_recurse++; break; } lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime); /* Give interrupts a chance while we spin. */ spinlock_exit(); while (m->mtx_lock != MTX_UNOWNED) { if (i++ < 10000000) cpu_spinwait(); else if (i < 60000000 || kdb_active || panicstr != NULL) DELAY(1); else _mtx_lock_spin_failed(m); cpu_spinwait(); if (m != td->td_lock) goto retry; } spinlock_enter(); } if (m == td->td_lock) break; __mtx_unlock_spin(m); /* does spinlock_exit() */ #ifdef KDTRACE_HOOKS spin_cnt++; #endif } if (m->mtx_recurse == 0) LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, m, contested, waittime, (file), (line)); LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, line); WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); LOCKSTAT_RECORD1(LS_THREAD_LOCK_SPIN, m, spin_cnt); } struct mtx * thread_lock_block(struct thread *td) { struct mtx *lock; THREAD_LOCK_ASSERT(td, MA_OWNED); lock = td->td_lock; td->td_lock = &blocked_lock; mtx_unlock_spin(lock); return (lock); } void thread_lock_unblock(struct thread *td, struct mtx *new) { mtx_assert(new, MA_OWNED); MPASS(td->td_lock == &blocked_lock); atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new); } void thread_lock_set(struct thread *td, struct mtx *new) { struct mtx *lock; mtx_assert(new, MA_OWNED); THREAD_LOCK_ASSERT(td, MA_OWNED); lock = td->td_lock; td->td_lock = new; mtx_unlock_spin(lock); } /* * _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock. * * We are only called here if the lock is recursed or contested (i.e. we * need to wake up a blocked thread). */ void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line) { struct turnstile *ts; + + if (SCHEDULER_STOPPED()) + return; if (mtx_recursed(m)) { if (--(m->mtx_recurse) == 0) atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED); if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m); return; } /* * We have to lock the chain before the turnstile so this turnstile * can be removed from the hash list if it is empty. */ turnstile_chain_lock(&m->lock_object); ts = turnstile_lookup(&m->lock_object); if (LOCK_LOG_TEST(&m->lock_object, opts)) CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m); MPASS(ts != NULL); turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE); _mtx_release_lock_quick(m); /* * This turnstile is now no longer associated with the mutex. We can * unlock the chain lock so a new turnstile may take it's place. */ turnstile_unpend(ts, TS_EXCLUSIVE_LOCK); turnstile_chain_unlock(&m->lock_object); } /* * All the unlocking of MTX_SPIN locks is done inline. * See the __mtx_unlock_spin() macro for the details. */ /* * The backing function for the INVARIANTS-enabled mtx_assert() */ #ifdef INVARIANT_SUPPORT void _mtx_assert(const struct mtx *m, int what, const char *file, int line) { if (panicstr != NULL || dumping) return; switch (what) { case MA_OWNED: case MA_OWNED | MA_RECURSED: case MA_OWNED | MA_NOTRECURSED: if (!mtx_owned(m)) panic("mutex %s not owned at %s:%d", m->lock_object.lo_name, file, line); if (mtx_recursed(m)) { if ((what & MA_NOTRECURSED) != 0) panic("mutex %s recursed at %s:%d", m->lock_object.lo_name, file, line); } else if ((what & MA_RECURSED) != 0) { panic("mutex %s unrecursed at %s:%d", m->lock_object.lo_name, file, line); } break; case MA_NOTOWNED: if (mtx_owned(m)) panic("mutex %s owned at %s:%d", m->lock_object.lo_name, file, line); break; default: panic("unknown mtx_assert at %s:%d", file, line); } } #endif /* * The MUTEX_DEBUG-enabled mtx_validate() * * Most of these checks have been moved off into the LO_INITIALIZED flag * maintained by the witness code. */ #ifdef MUTEX_DEBUG void mtx_validate(struct mtx *); void mtx_validate(struct mtx *m) { /* * XXX: When kernacc() does not require Giant we can reenable this check */ #ifdef notyet /* * Can't call kernacc() from early init386(), especially when * initializing Giant mutex, because some stuff in kernacc() * requires Giant itself. */ if (!cold) if (!kernacc((caddr_t)m, sizeof(m), VM_PROT_READ | VM_PROT_WRITE)) panic("Can't read and write to mutex %p", m); #endif } #endif /* * General init routine used by the MTX_SYSINIT() macro. */ void mtx_sysinit(void *arg) { struct mtx_args *margs = arg; mtx_init(margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts); } /* * Mutex initialization routine; initialize lock `m' of type contained in * `opts' with options contained in `opts' and name `name.' The optional * lock type `type' is used as a general lock category name for use with * witness. */ void mtx_init(struct mtx *m, const char *name, const char *type, int opts) { struct lock_class *class; int flags; MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE | MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE)) == 0); ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock, ("%s: mtx_lock not aligned for %s: %p", __func__, name, &m->mtx_lock)); #ifdef MUTEX_DEBUG /* Diagnostic and error correction */ mtx_validate(m); #endif /* Determine lock class and lock flags. */ if (opts & MTX_SPIN) class = &lock_class_mtx_spin; else class = &lock_class_mtx_sleep; flags = 0; if (opts & MTX_QUIET) flags |= LO_QUIET; if (opts & MTX_RECURSE) flags |= LO_RECURSABLE; if ((opts & MTX_NOWITNESS) == 0) flags |= LO_WITNESS; if (opts & MTX_DUPOK) flags |= LO_DUPOK; if (opts & MTX_NOPROFILE) flags |= LO_NOPROFILE; /* Initialize mutex. */ m->mtx_lock = MTX_UNOWNED; m->mtx_recurse = 0; lock_init(&m->lock_object, class, name, type, flags); } /* * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be * passed in as a flag here because if the corresponding mtx_init() was * called with MTX_QUIET set, then it will already be set in the mutex's * flags. */ void mtx_destroy(struct mtx *m) { if (!mtx_owned(m)) MPASS(mtx_unowned(m)); else { MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0); /* Perform the non-mtx related part of mtx_unlock_spin(). */ if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin) spinlock_exit(); else curthread->td_locks--; lock_profile_release_lock(&m->lock_object); /* Tell witness this isn't locked to make it happy. */ WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__, __LINE__); } m->mtx_lock = MTX_DESTROYED; lock_destroy(&m->lock_object); } /* * Intialize the mutex code and system mutexes. This is called from the MD * startup code prior to mi_startup(). The per-CPU data space needs to be * setup before this is called. */ void mutex_init(void) { /* Setup turnstiles so that sleep mutexes work. */ init_turnstiles(); /* * Initialize mutexes. */ mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE); mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN); blocked_lock.mtx_lock = 0xdeadc0de; /* Always blocked. */ mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK); mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN | MTX_RECURSE); mtx_init(&devmtx, "cdev", NULL, MTX_DEF); mtx_lock(&Giant); } #ifdef DDB void db_show_mtx(const struct lock_object *lock) { struct thread *td; const struct mtx *m; m = (const struct mtx *)lock; db_printf(" flags: {"); if (LOCK_CLASS(lock) == &lock_class_mtx_spin) db_printf("SPIN"); else db_printf("DEF"); if (m->lock_object.lo_flags & LO_RECURSABLE) db_printf(", RECURSE"); if (m->lock_object.lo_flags & LO_DUPOK) db_printf(", DUPOK"); db_printf("}\n"); db_printf(" state: {"); if (mtx_unowned(m)) db_printf("UNOWNED"); else if (mtx_destroyed(m)) db_printf("DESTROYED"); else { db_printf("OWNED"); if (m->mtx_lock & MTX_CONTESTED) db_printf(", CONTESTED"); if (m->mtx_lock & MTX_RECURSED) db_printf(", RECURSED"); } db_printf("}\n"); if (!mtx_unowned(m) && !mtx_destroyed(m)) { td = mtx_owner(m); db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td, td->td_tid, td->td_proc->p_pid, td->td_name); if (mtx_recursed(m)) db_printf(" recursed: %d\n", m->mtx_recurse); } } #endif Index: head/sys/kern/kern_rmlock.c =================================================================== --- head/sys/kern/kern_rmlock.c (revision 228423) +++ head/sys/kern/kern_rmlock.c (revision 228424) @@ -1,589 +1,611 @@ /*- * Copyright (c) 2007 Stephan Uphoff * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the author nor the names of any co-contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * Machine independent bits of reader/writer lock implementation. */ #include __FBSDID("$FreeBSD$"); #include "opt_ddb.h" #include "opt_kdtrace.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DDB #include #endif #define RMPF_ONQUEUE 1 #define RMPF_SIGNAL 2 /* * To support usage of rmlock in CVs and msleep yet another list for the * priority tracker would be needed. Using this lock for cv and msleep also * does not seem very useful */ static __inline void compiler_memory_barrier(void) { __asm __volatile("":::"memory"); } static void assert_rm(const struct lock_object *lock, int what); static void lock_rm(struct lock_object *lock, int how); #ifdef KDTRACE_HOOKS static int owner_rm(const struct lock_object *lock, struct thread **owner); #endif static int unlock_rm(struct lock_object *lock); struct lock_class lock_class_rm = { .lc_name = "rm", .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE, .lc_assert = assert_rm, #if 0 #ifdef DDB .lc_ddb_show = db_show_rwlock, #endif #endif .lc_lock = lock_rm, .lc_unlock = unlock_rm, #ifdef KDTRACE_HOOKS .lc_owner = owner_rm, #endif }; static void assert_rm(const struct lock_object *lock, int what) { panic("assert_rm called"); } static void lock_rm(struct lock_object *lock, int how) { panic("lock_rm called"); } static int unlock_rm(struct lock_object *lock) { panic("unlock_rm called"); } #ifdef KDTRACE_HOOKS static int owner_rm(const struct lock_object *lock, struct thread **owner) { panic("owner_rm called"); } #endif static struct mtx rm_spinlock; MTX_SYSINIT(rm_spinlock, &rm_spinlock, "rm_spinlock", MTX_SPIN); /* * Add or remove tracker from per-cpu list. * * The per-cpu list can be traversed at any time in forward direction from an * interrupt on the *local* cpu. */ static void inline rm_tracker_add(struct pcpu *pc, struct rm_priotracker *tracker) { struct rm_queue *next; /* Initialize all tracker pointers */ tracker->rmp_cpuQueue.rmq_prev = &pc->pc_rm_queue; next = pc->pc_rm_queue.rmq_next; tracker->rmp_cpuQueue.rmq_next = next; /* rmq_prev is not used during froward traversal. */ next->rmq_prev = &tracker->rmp_cpuQueue; /* Update pointer to first element. */ pc->pc_rm_queue.rmq_next = &tracker->rmp_cpuQueue; } static void inline rm_tracker_remove(struct pcpu *pc, struct rm_priotracker *tracker) { struct rm_queue *next, *prev; next = tracker->rmp_cpuQueue.rmq_next; prev = tracker->rmp_cpuQueue.rmq_prev; /* Not used during forward traversal. */ next->rmq_prev = prev; /* Remove from list. */ prev->rmq_next = next; } static void rm_cleanIPI(void *arg) { struct pcpu *pc; struct rmlock *rm = arg; struct rm_priotracker *tracker; struct rm_queue *queue; pc = pcpu_find(curcpu); for (queue = pc->pc_rm_queue.rmq_next; queue != &pc->pc_rm_queue; queue = queue->rmq_next) { tracker = (struct rm_priotracker *)queue; if (tracker->rmp_rmlock == rm && tracker->rmp_flags == 0) { tracker->rmp_flags = RMPF_ONQUEUE; mtx_lock_spin(&rm_spinlock); LIST_INSERT_HEAD(&rm->rm_activeReaders, tracker, rmp_qentry); mtx_unlock_spin(&rm_spinlock); } } } CTASSERT((RM_SLEEPABLE & LO_CLASSFLAGS) == RM_SLEEPABLE); void rm_init_flags(struct rmlock *rm, const char *name, int opts) { int liflags; liflags = 0; if (!(opts & RM_NOWITNESS)) liflags |= LO_WITNESS; if (opts & RM_RECURSE) liflags |= LO_RECURSABLE; rm->rm_writecpus = all_cpus; LIST_INIT(&rm->rm_activeReaders); if (opts & RM_SLEEPABLE) { liflags |= RM_SLEEPABLE; sx_init_flags(&rm->rm_lock_sx, "rmlock_sx", SX_RECURSE); } else mtx_init(&rm->rm_lock_mtx, name, "rmlock_mtx", MTX_NOWITNESS); lock_init(&rm->lock_object, &lock_class_rm, name, NULL, liflags); } void rm_init(struct rmlock *rm, const char *name) { rm_init_flags(rm, name, 0); } void rm_destroy(struct rmlock *rm) { if (rm->lock_object.lo_flags & RM_SLEEPABLE) sx_destroy(&rm->rm_lock_sx); else mtx_destroy(&rm->rm_lock_mtx); lock_destroy(&rm->lock_object); } int rm_wowned(const struct rmlock *rm) { if (rm->lock_object.lo_flags & RM_SLEEPABLE) return (sx_xlocked(&rm->rm_lock_sx)); else return (mtx_owned(&rm->rm_lock_mtx)); } void rm_sysinit(void *arg) { struct rm_args *args = arg; rm_init(args->ra_rm, args->ra_desc); } void rm_sysinit_flags(void *arg) { struct rm_args_flags *args = arg; rm_init_flags(args->ra_rm, args->ra_desc, args->ra_opts); } static int _rm_rlock_hard(struct rmlock *rm, struct rm_priotracker *tracker, int trylock) { struct pcpu *pc; struct rm_queue *queue; struct rm_priotracker *atracker; critical_enter(); pc = pcpu_find(curcpu); /* Check if we just need to do a proper critical_exit. */ if (!CPU_ISSET(pc->pc_cpuid, &rm->rm_writecpus)) { critical_exit(); return (1); } /* Remove our tracker from the per-cpu list. */ rm_tracker_remove(pc, tracker); /* Check to see if the IPI granted us the lock after all. */ if (tracker->rmp_flags) { /* Just add back tracker - we hold the lock. */ rm_tracker_add(pc, tracker); critical_exit(); return (1); } /* * We allow readers to aquire a lock even if a writer is blocked if * the lock is recursive and the reader already holds the lock. */ if ((rm->lock_object.lo_flags & LO_RECURSABLE) != 0) { /* * Just grant the lock if this thread already has a tracker * for this lock on the per-cpu queue. */ for (queue = pc->pc_rm_queue.rmq_next; queue != &pc->pc_rm_queue; queue = queue->rmq_next) { atracker = (struct rm_priotracker *)queue; if ((atracker->rmp_rmlock == rm) && (atracker->rmp_thread == tracker->rmp_thread)) { mtx_lock_spin(&rm_spinlock); LIST_INSERT_HEAD(&rm->rm_activeReaders, tracker, rmp_qentry); tracker->rmp_flags = RMPF_ONQUEUE; mtx_unlock_spin(&rm_spinlock); rm_tracker_add(pc, tracker); critical_exit(); return (1); } } } sched_unpin(); critical_exit(); if (trylock) { if (rm->lock_object.lo_flags & RM_SLEEPABLE) { if (!sx_try_xlock(&rm->rm_lock_sx)) return (0); } else { if (!mtx_trylock(&rm->rm_lock_mtx)) return (0); } } else { if (rm->lock_object.lo_flags & RM_SLEEPABLE) sx_xlock(&rm->rm_lock_sx); else mtx_lock(&rm->rm_lock_mtx); } critical_enter(); pc = pcpu_find(curcpu); CPU_CLR(pc->pc_cpuid, &rm->rm_writecpus); rm_tracker_add(pc, tracker); sched_pin(); critical_exit(); if (rm->lock_object.lo_flags & RM_SLEEPABLE) sx_xunlock(&rm->rm_lock_sx); else mtx_unlock(&rm->rm_lock_mtx); return (1); } int _rm_rlock(struct rmlock *rm, struct rm_priotracker *tracker, int trylock) { struct thread *td = curthread; struct pcpu *pc; + if (SCHEDULER_STOPPED()) + return (1); + tracker->rmp_flags = 0; tracker->rmp_thread = td; tracker->rmp_rmlock = rm; td->td_critnest++; /* critical_enter(); */ compiler_memory_barrier(); pc = cpuid_to_pcpu[td->td_oncpu]; /* pcpu_find(td->td_oncpu); */ rm_tracker_add(pc, tracker); sched_pin(); compiler_memory_barrier(); td->td_critnest--; /* * Fast path to combine two common conditions into a single * conditional jump. */ if (0 == (td->td_owepreempt | CPU_ISSET(pc->pc_cpuid, &rm->rm_writecpus))) return (1); /* We do not have a read token and need to acquire one. */ return _rm_rlock_hard(rm, tracker, trylock); } static void _rm_unlock_hard(struct thread *td,struct rm_priotracker *tracker) { if (td->td_owepreempt) { td->td_critnest++; critical_exit(); } if (!tracker->rmp_flags) return; mtx_lock_spin(&rm_spinlock); LIST_REMOVE(tracker, rmp_qentry); if (tracker->rmp_flags & RMPF_SIGNAL) { struct rmlock *rm; struct turnstile *ts; rm = tracker->rmp_rmlock; turnstile_chain_lock(&rm->lock_object); mtx_unlock_spin(&rm_spinlock); ts = turnstile_lookup(&rm->lock_object); turnstile_signal(ts, TS_EXCLUSIVE_QUEUE); turnstile_unpend(ts, TS_EXCLUSIVE_LOCK); turnstile_chain_unlock(&rm->lock_object); } else mtx_unlock_spin(&rm_spinlock); } void _rm_runlock(struct rmlock *rm, struct rm_priotracker *tracker) { struct pcpu *pc; struct thread *td = tracker->rmp_thread; + if (SCHEDULER_STOPPED()) + return; + td->td_critnest++; /* critical_enter(); */ pc = cpuid_to_pcpu[td->td_oncpu]; /* pcpu_find(td->td_oncpu); */ rm_tracker_remove(pc, tracker); td->td_critnest--; sched_unpin(); if (0 == (td->td_owepreempt | tracker->rmp_flags)) return; _rm_unlock_hard(td, tracker); } void _rm_wlock(struct rmlock *rm) { struct rm_priotracker *prio; struct turnstile *ts; cpuset_t readcpus; + if (SCHEDULER_STOPPED()) + return; + if (rm->lock_object.lo_flags & RM_SLEEPABLE) sx_xlock(&rm->rm_lock_sx); else mtx_lock(&rm->rm_lock_mtx); if (CPU_CMP(&rm->rm_writecpus, &all_cpus)) { /* Get all read tokens back */ readcpus = all_cpus; CPU_NAND(&readcpus, &rm->rm_writecpus); rm->rm_writecpus = all_cpus; /* * Assumes rm->rm_writecpus update is visible on other CPUs * before rm_cleanIPI is called. */ #ifdef SMP smp_rendezvous_cpus(readcpus, smp_no_rendevous_barrier, rm_cleanIPI, smp_no_rendevous_barrier, rm); #else rm_cleanIPI(rm); #endif mtx_lock_spin(&rm_spinlock); while ((prio = LIST_FIRST(&rm->rm_activeReaders)) != NULL) { ts = turnstile_trywait(&rm->lock_object); prio->rmp_flags = RMPF_ONQUEUE | RMPF_SIGNAL; mtx_unlock_spin(&rm_spinlock); turnstile_wait(ts, prio->rmp_thread, TS_EXCLUSIVE_QUEUE); mtx_lock_spin(&rm_spinlock); } mtx_unlock_spin(&rm_spinlock); } } void _rm_wunlock(struct rmlock *rm) { if (rm->lock_object.lo_flags & RM_SLEEPABLE) sx_xunlock(&rm->rm_lock_sx); else mtx_unlock(&rm->rm_lock_mtx); } #ifdef LOCK_DEBUG void _rm_wlock_debug(struct rmlock *rm, const char *file, int line) { + if (SCHEDULER_STOPPED()) + return; + WITNESS_CHECKORDER(&rm->lock_object, LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); _rm_wlock(rm); LOCK_LOG_LOCK("RMWLOCK", &rm->lock_object, 0, 0, file, line); if (rm->lock_object.lo_flags & RM_SLEEPABLE) WITNESS_LOCK(&rm->rm_lock_sx.lock_object, LOP_EXCLUSIVE, file, line); else WITNESS_LOCK(&rm->lock_object, LOP_EXCLUSIVE, file, line); curthread->td_locks++; } void _rm_wunlock_debug(struct rmlock *rm, const char *file, int line) { + if (SCHEDULER_STOPPED()) + return; + curthread->td_locks--; if (rm->lock_object.lo_flags & RM_SLEEPABLE) WITNESS_UNLOCK(&rm->rm_lock_sx.lock_object, LOP_EXCLUSIVE, file, line); else WITNESS_UNLOCK(&rm->lock_object, LOP_EXCLUSIVE, file, line); LOCK_LOG_LOCK("RMWUNLOCK", &rm->lock_object, 0, 0, file, line); _rm_wunlock(rm); } int _rm_rlock_debug(struct rmlock *rm, struct rm_priotracker *tracker, int trylock, const char *file, int line) { + + if (SCHEDULER_STOPPED()) + return (1); + if (!trylock && (rm->lock_object.lo_flags & RM_SLEEPABLE)) WITNESS_CHECKORDER(&rm->rm_lock_sx.lock_object, LOP_NEWORDER, file, line, NULL); WITNESS_CHECKORDER(&rm->lock_object, LOP_NEWORDER, file, line, NULL); if (_rm_rlock(rm, tracker, trylock)) { LOCK_LOG_LOCK("RMRLOCK", &rm->lock_object, 0, 0, file, line); WITNESS_LOCK(&rm->lock_object, 0, file, line); curthread->td_locks++; return (1); } return (0); } void _rm_runlock_debug(struct rmlock *rm, struct rm_priotracker *tracker, const char *file, int line) { + + if (SCHEDULER_STOPPED()) + return; curthread->td_locks--; WITNESS_UNLOCK(&rm->lock_object, 0, file, line); LOCK_LOG_LOCK("RMRUNLOCK", &rm->lock_object, 0, 0, file, line); _rm_runlock(rm, tracker); } #else /* * Just strip out file and line arguments if no lock debugging is enabled in * the kernel - we are called from a kernel module. */ void _rm_wlock_debug(struct rmlock *rm, const char *file, int line) { _rm_wlock(rm); } void _rm_wunlock_debug(struct rmlock *rm, const char *file, int line) { _rm_wunlock(rm); } int _rm_rlock_debug(struct rmlock *rm, struct rm_priotracker *tracker, int trylock, const char *file, int line) { return _rm_rlock(rm, tracker, trylock); } void _rm_runlock_debug(struct rmlock *rm, struct rm_priotracker *tracker, const char *file, int line) { _rm_runlock(rm, tracker); } #endif Index: head/sys/kern/kern_rwlock.c =================================================================== --- head/sys/kern/kern_rwlock.c (revision 228423) +++ head/sys/kern/kern_rwlock.c (revision 228424) @@ -1,1127 +1,1155 @@ /*- * Copyright (c) 2006 John Baldwin * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the author nor the names of any co-contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * Machine independent bits of reader/writer lock implementation. */ #include __FBSDID("$FreeBSD$"); #include "opt_ddb.h" #include "opt_kdtrace.h" #include "opt_no_adaptive_rwlocks.h" #include #include #include #include #include #include #include #include #include #include #include #if defined(SMP) && !defined(NO_ADAPTIVE_RWLOCKS) #define ADAPTIVE_RWLOCKS #endif #ifdef ADAPTIVE_RWLOCKS static int rowner_retries = 10; static int rowner_loops = 10000; static SYSCTL_NODE(_debug, OID_AUTO, rwlock, CTLFLAG_RD, NULL, "rwlock debugging"); SYSCTL_INT(_debug_rwlock, OID_AUTO, retry, CTLFLAG_RW, &rowner_retries, 0, ""); SYSCTL_INT(_debug_rwlock, OID_AUTO, loops, CTLFLAG_RW, &rowner_loops, 0, ""); #endif #ifdef DDB #include static void db_show_rwlock(const struct lock_object *lock); #endif static void assert_rw(const struct lock_object *lock, int what); static void lock_rw(struct lock_object *lock, int how); #ifdef KDTRACE_HOOKS static int owner_rw(const struct lock_object *lock, struct thread **owner); #endif static int unlock_rw(struct lock_object *lock); struct lock_class lock_class_rw = { .lc_name = "rw", .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE | LC_UPGRADABLE, .lc_assert = assert_rw, #ifdef DDB .lc_ddb_show = db_show_rwlock, #endif .lc_lock = lock_rw, .lc_unlock = unlock_rw, #ifdef KDTRACE_HOOKS .lc_owner = owner_rw, #endif }; /* * Return a pointer to the owning thread if the lock is write-locked or * NULL if the lock is unlocked or read-locked. */ #define rw_wowner(rw) \ ((rw)->rw_lock & RW_LOCK_READ ? NULL : \ (struct thread *)RW_OWNER((rw)->rw_lock)) /* * Returns if a write owner is recursed. Write ownership is not assured * here and should be previously checked. */ #define rw_recursed(rw) ((rw)->rw_recurse != 0) /* * Return true if curthread helds the lock. */ #define rw_wlocked(rw) (rw_wowner((rw)) == curthread) /* * Return a pointer to the owning thread for this lock who should receive * any priority lent by threads that block on this lock. Currently this * is identical to rw_wowner(). */ #define rw_owner(rw) rw_wowner(rw) #ifndef INVARIANTS #define _rw_assert(rw, what, file, line) #endif void assert_rw(const struct lock_object *lock, int what) { rw_assert((const struct rwlock *)lock, what); } void lock_rw(struct lock_object *lock, int how) { struct rwlock *rw; rw = (struct rwlock *)lock; if (how) rw_wlock(rw); else rw_rlock(rw); } int unlock_rw(struct lock_object *lock) { struct rwlock *rw; rw = (struct rwlock *)lock; rw_assert(rw, RA_LOCKED | LA_NOTRECURSED); if (rw->rw_lock & RW_LOCK_READ) { rw_runlock(rw); return (0); } else { rw_wunlock(rw); return (1); } } #ifdef KDTRACE_HOOKS int owner_rw(const struct lock_object *lock, struct thread **owner) { const struct rwlock *rw = (const struct rwlock *)lock; uintptr_t x = rw->rw_lock; *owner = rw_wowner(rw); return ((x & RW_LOCK_READ) != 0 ? (RW_READERS(x) != 0) : (*owner != NULL)); } #endif void rw_init_flags(struct rwlock *rw, const char *name, int opts) { int flags; MPASS((opts & ~(RW_DUPOK | RW_NOPROFILE | RW_NOWITNESS | RW_QUIET | RW_RECURSE)) == 0); ASSERT_ATOMIC_LOAD_PTR(rw->rw_lock, ("%s: rw_lock not aligned for %s: %p", __func__, name, &rw->rw_lock)); flags = LO_UPGRADABLE; if (opts & RW_DUPOK) flags |= LO_DUPOK; if (opts & RW_NOPROFILE) flags |= LO_NOPROFILE; if (!(opts & RW_NOWITNESS)) flags |= LO_WITNESS; if (opts & RW_RECURSE) flags |= LO_RECURSABLE; if (opts & RW_QUIET) flags |= LO_QUIET; rw->rw_lock = RW_UNLOCKED; rw->rw_recurse = 0; lock_init(&rw->lock_object, &lock_class_rw, name, NULL, flags); } void rw_destroy(struct rwlock *rw) { KASSERT(rw->rw_lock == RW_UNLOCKED, ("rw lock %p not unlocked", rw)); KASSERT(rw->rw_recurse == 0, ("rw lock %p still recursed", rw)); rw->rw_lock = RW_DESTROYED; lock_destroy(&rw->lock_object); } void rw_sysinit(void *arg) { struct rw_args *args = arg; rw_init(args->ra_rw, args->ra_desc); } void rw_sysinit_flags(void *arg) { struct rw_args_flags *args = arg; rw_init_flags(args->ra_rw, args->ra_desc, args->ra_flags); } int rw_wowned(const struct rwlock *rw) { return (rw_wowner(rw) == curthread); } void _rw_wlock(struct rwlock *rw, const char *file, int line) { + if (SCHEDULER_STOPPED()) + return; MPASS(curthread != NULL); KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_wlock() of destroyed rwlock @ %s:%d", file, line)); WITNESS_CHECKORDER(&rw->lock_object, LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); __rw_wlock(rw, curthread, file, line); LOCK_LOG_LOCK("WLOCK", &rw->lock_object, 0, rw->rw_recurse, file, line); WITNESS_LOCK(&rw->lock_object, LOP_EXCLUSIVE, file, line); curthread->td_locks++; } int _rw_try_wlock(struct rwlock *rw, const char *file, int line) { int rval; + if (SCHEDULER_STOPPED()) + return (1); + KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_try_wlock() of destroyed rwlock @ %s:%d", file, line)); if (rw_wlocked(rw) && (rw->lock_object.lo_flags & LO_RECURSABLE) != 0) { rw->rw_recurse++; rval = 1; } else rval = atomic_cmpset_acq_ptr(&rw->rw_lock, RW_UNLOCKED, (uintptr_t)curthread); LOCK_LOG_TRY("WLOCK", &rw->lock_object, 0, rval, file, line); if (rval) { WITNESS_LOCK(&rw->lock_object, LOP_EXCLUSIVE | LOP_TRYLOCK, file, line); curthread->td_locks++; } return (rval); } void _rw_wunlock(struct rwlock *rw, const char *file, int line) { + if (SCHEDULER_STOPPED()) + return; MPASS(curthread != NULL); KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_wunlock() of destroyed rwlock @ %s:%d", file, line)); _rw_assert(rw, RA_WLOCKED, file, line); curthread->td_locks--; WITNESS_UNLOCK(&rw->lock_object, LOP_EXCLUSIVE, file, line); LOCK_LOG_LOCK("WUNLOCK", &rw->lock_object, 0, rw->rw_recurse, file, line); if (!rw_recursed(rw)) LOCKSTAT_PROFILE_RELEASE_LOCK(LS_RW_WUNLOCK_RELEASE, rw); __rw_wunlock(rw, curthread, file, line); } /* * Determines whether a new reader can acquire a lock. Succeeds if the * reader already owns a read lock and the lock is locked for read to * prevent deadlock from reader recursion. Also succeeds if the lock * is unlocked and has no writer waiters or spinners. Failing otherwise * prioritizes writers before readers. */ #define RW_CAN_READ(_rw) \ ((curthread->td_rw_rlocks && (_rw) & RW_LOCK_READ) || ((_rw) & \ (RW_LOCK_READ | RW_LOCK_WRITE_WAITERS | RW_LOCK_WRITE_SPINNER)) == \ RW_LOCK_READ) void _rw_rlock(struct rwlock *rw, const char *file, int line) { struct turnstile *ts; #ifdef ADAPTIVE_RWLOCKS volatile struct thread *owner; int spintries = 0; int i; #endif #ifdef LOCK_PROFILING uint64_t waittime = 0; int contested = 0; #endif uintptr_t v; #ifdef KDTRACE_HOOKS uint64_t spin_cnt = 0; uint64_t sleep_cnt = 0; int64_t sleep_time = 0; #endif + if (SCHEDULER_STOPPED()) + return; + KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_rlock() of destroyed rwlock @ %s:%d", file, line)); KASSERT(rw_wowner(rw) != curthread, ("%s (%s): wlock already held @ %s:%d", __func__, rw->lock_object.lo_name, file, line)); WITNESS_CHECKORDER(&rw->lock_object, LOP_NEWORDER, file, line, NULL); for (;;) { #ifdef KDTRACE_HOOKS spin_cnt++; #endif /* * Handle the easy case. If no other thread has a write * lock, then try to bump up the count of read locks. Note * that we have to preserve the current state of the * RW_LOCK_WRITE_WAITERS flag. If we fail to acquire a * read lock, then rw_lock must have changed, so restart * the loop. Note that this handles the case of a * completely unlocked rwlock since such a lock is encoded * as a read lock with no waiters. */ v = rw->rw_lock; if (RW_CAN_READ(v)) { /* * The RW_LOCK_READ_WAITERS flag should only be set * if the lock has been unlocked and write waiters * were present. */ if (atomic_cmpset_acq_ptr(&rw->rw_lock, v, v + RW_ONE_READER)) { if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR4(KTR_LOCK, "%s: %p succeed %p -> %p", __func__, rw, (void *)v, (void *)(v + RW_ONE_READER)); break; } continue; } lock_profile_obtain_lock_failed(&rw->lock_object, &contested, &waittime); #ifdef ADAPTIVE_RWLOCKS /* * If the owner is running on another CPU, spin until * the owner stops running or the state of the lock * changes. */ if ((v & RW_LOCK_READ) == 0) { owner = (struct thread *)RW_OWNER(v); if (TD_IS_RUNNING(owner)) { if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, rw, owner); while ((struct thread*)RW_OWNER(rw->rw_lock) == owner && TD_IS_RUNNING(owner)) { cpu_spinwait(); #ifdef KDTRACE_HOOKS spin_cnt++; #endif } continue; } } else if (spintries < rowner_retries) { spintries++; for (i = 0; i < rowner_loops; i++) { v = rw->rw_lock; if ((v & RW_LOCK_READ) == 0 || RW_CAN_READ(v)) break; cpu_spinwait(); } if (i != rowner_loops) continue; } #endif /* * Okay, now it's the hard case. Some other thread already * has a write lock or there are write waiters present, * acquire the turnstile lock so we can begin the process * of blocking. */ ts = turnstile_trywait(&rw->lock_object); /* * The lock might have been released while we spun, so * recheck its state and restart the loop if needed. */ v = rw->rw_lock; if (RW_CAN_READ(v)) { turnstile_cancel(ts); continue; } #ifdef ADAPTIVE_RWLOCKS /* * The current lock owner might have started executing * on another CPU (or the lock could have changed * owners) while we were waiting on the turnstile * chain lock. If so, drop the turnstile lock and try * again. */ if ((v & RW_LOCK_READ) == 0) { owner = (struct thread *)RW_OWNER(v); if (TD_IS_RUNNING(owner)) { turnstile_cancel(ts); continue; } } #endif /* * The lock is held in write mode or it already has waiters. */ MPASS(!RW_CAN_READ(v)); /* * If the RW_LOCK_READ_WAITERS flag is already set, then * we can go ahead and block. If it is not set then try * to set it. If we fail to set it drop the turnstile * lock and restart the loop. */ if (!(v & RW_LOCK_READ_WAITERS)) { if (!atomic_cmpset_ptr(&rw->rw_lock, v, v | RW_LOCK_READ_WAITERS)) { turnstile_cancel(ts); continue; } if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p set read waiters flag", __func__, rw); } /* * We were unable to acquire the lock and the read waiters * flag is set, so we must block on the turnstile. */ if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p blocking on turnstile", __func__, rw); #ifdef KDTRACE_HOOKS sleep_time -= lockstat_nsecs(); #endif turnstile_wait(ts, rw_owner(rw), TS_SHARED_QUEUE); #ifdef KDTRACE_HOOKS sleep_time += lockstat_nsecs(); sleep_cnt++; #endif if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p resuming from turnstile", __func__, rw); } /* * TODO: acquire "owner of record" here. Here be turnstile dragons * however. turnstiles don't like owners changing between calls to * turnstile_wait() currently. */ LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_RW_RLOCK_ACQUIRE, rw, contested, waittime, file, line); LOCK_LOG_LOCK("RLOCK", &rw->lock_object, 0, 0, file, line); WITNESS_LOCK(&rw->lock_object, 0, file, line); curthread->td_locks++; curthread->td_rw_rlocks++; #ifdef KDTRACE_HOOKS if (sleep_time) LOCKSTAT_RECORD1(LS_RW_RLOCK_BLOCK, rw, sleep_time); /* * Record only the loops spinning and not sleeping. */ if (spin_cnt > sleep_cnt) LOCKSTAT_RECORD1(LS_RW_RLOCK_SPIN, rw, (spin_cnt - sleep_cnt)); #endif } int _rw_try_rlock(struct rwlock *rw, const char *file, int line) { uintptr_t x; + if (SCHEDULER_STOPPED()) + return (1); + for (;;) { x = rw->rw_lock; KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_try_rlock() of destroyed rwlock @ %s:%d", file, line)); if (!(x & RW_LOCK_READ)) break; if (atomic_cmpset_acq_ptr(&rw->rw_lock, x, x + RW_ONE_READER)) { LOCK_LOG_TRY("RLOCK", &rw->lock_object, 0, 1, file, line); WITNESS_LOCK(&rw->lock_object, LOP_TRYLOCK, file, line); curthread->td_locks++; curthread->td_rw_rlocks++; return (1); } } LOCK_LOG_TRY("RLOCK", &rw->lock_object, 0, 0, file, line); return (0); } void _rw_runlock(struct rwlock *rw, const char *file, int line) { struct turnstile *ts; uintptr_t x, v, queue; + if (SCHEDULER_STOPPED()) + return; + KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_runlock() of destroyed rwlock @ %s:%d", file, line)); _rw_assert(rw, RA_RLOCKED, file, line); curthread->td_locks--; curthread->td_rw_rlocks--; WITNESS_UNLOCK(&rw->lock_object, 0, file, line); LOCK_LOG_LOCK("RUNLOCK", &rw->lock_object, 0, 0, file, line); /* TODO: drop "owner of record" here. */ for (;;) { /* * See if there is more than one read lock held. If so, * just drop one and return. */ x = rw->rw_lock; if (RW_READERS(x) > 1) { if (atomic_cmpset_rel_ptr(&rw->rw_lock, x, x - RW_ONE_READER)) { if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR4(KTR_LOCK, "%s: %p succeeded %p -> %p", __func__, rw, (void *)x, (void *)(x - RW_ONE_READER)); break; } continue; } /* * If there aren't any waiters for a write lock, then try * to drop it quickly. */ if (!(x & RW_LOCK_WAITERS)) { MPASS((x & ~RW_LOCK_WRITE_SPINNER) == RW_READERS_LOCK(1)); if (atomic_cmpset_rel_ptr(&rw->rw_lock, x, RW_UNLOCKED)) { if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p last succeeded", __func__, rw); break; } continue; } /* * Ok, we know we have waiters and we think we are the * last reader, so grab the turnstile lock. */ turnstile_chain_lock(&rw->lock_object); v = rw->rw_lock & (RW_LOCK_WAITERS | RW_LOCK_WRITE_SPINNER); MPASS(v & RW_LOCK_WAITERS); /* * Try to drop our lock leaving the lock in a unlocked * state. * * If you wanted to do explicit lock handoff you'd have to * do it here. You'd also want to use turnstile_signal() * and you'd have to handle the race where a higher * priority thread blocks on the write lock before the * thread you wakeup actually runs and have the new thread * "steal" the lock. For now it's a lot simpler to just * wakeup all of the waiters. * * As above, if we fail, then another thread might have * acquired a read lock, so drop the turnstile lock and * restart. */ x = RW_UNLOCKED; if (v & RW_LOCK_WRITE_WAITERS) { queue = TS_EXCLUSIVE_QUEUE; x |= (v & RW_LOCK_READ_WAITERS); } else queue = TS_SHARED_QUEUE; if (!atomic_cmpset_rel_ptr(&rw->rw_lock, RW_READERS_LOCK(1) | v, x)) { turnstile_chain_unlock(&rw->lock_object); continue; } if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p last succeeded with waiters", __func__, rw); /* * Ok. The lock is released and all that's left is to * wake up the waiters. Note that the lock might not be * free anymore, but in that case the writers will just * block again if they run before the new lock holder(s) * release the lock. */ ts = turnstile_lookup(&rw->lock_object); MPASS(ts != NULL); turnstile_broadcast(ts, queue); turnstile_unpend(ts, TS_SHARED_LOCK); turnstile_chain_unlock(&rw->lock_object); break; } LOCKSTAT_PROFILE_RELEASE_LOCK(LS_RW_RUNLOCK_RELEASE, rw); } /* * This function is called when we are unable to obtain a write lock on the * first try. This means that at least one other thread holds either a * read or write lock. */ void _rw_wlock_hard(struct rwlock *rw, uintptr_t tid, const char *file, int line) { struct turnstile *ts; #ifdef ADAPTIVE_RWLOCKS volatile struct thread *owner; int spintries = 0; int i; #endif uintptr_t v, x; #ifdef LOCK_PROFILING uint64_t waittime = 0; int contested = 0; #endif #ifdef KDTRACE_HOOKS uint64_t spin_cnt = 0; uint64_t sleep_cnt = 0; int64_t sleep_time = 0; #endif + if (SCHEDULER_STOPPED()) + return; + if (rw_wlocked(rw)) { KASSERT(rw->lock_object.lo_flags & LO_RECURSABLE, ("%s: recursing but non-recursive rw %s @ %s:%d\n", __func__, rw->lock_object.lo_name, file, line)); rw->rw_recurse++; if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p recursing", __func__, rw); return; } if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR5(KTR_LOCK, "%s: %s contested (lock=%p) at %s:%d", __func__, rw->lock_object.lo_name, (void *)rw->rw_lock, file, line); while (!_rw_write_lock(rw, tid)) { #ifdef KDTRACE_HOOKS spin_cnt++; #endif lock_profile_obtain_lock_failed(&rw->lock_object, &contested, &waittime); #ifdef ADAPTIVE_RWLOCKS /* * If the lock is write locked and the owner is * running on another CPU, spin until the owner stops * running or the state of the lock changes. */ v = rw->rw_lock; owner = (struct thread *)RW_OWNER(v); if (!(v & RW_LOCK_READ) && TD_IS_RUNNING(owner)) { if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, rw, owner); while ((struct thread*)RW_OWNER(rw->rw_lock) == owner && TD_IS_RUNNING(owner)) { cpu_spinwait(); #ifdef KDTRACE_HOOKS spin_cnt++; #endif } continue; } if ((v & RW_LOCK_READ) && RW_READERS(v) && spintries < rowner_retries) { if (!(v & RW_LOCK_WRITE_SPINNER)) { if (!atomic_cmpset_ptr(&rw->rw_lock, v, v | RW_LOCK_WRITE_SPINNER)) { continue; } } spintries++; for (i = 0; i < rowner_loops; i++) { if ((rw->rw_lock & RW_LOCK_WRITE_SPINNER) == 0) break; cpu_spinwait(); } #ifdef KDTRACE_HOOKS spin_cnt += rowner_loops - i; #endif if (i != rowner_loops) continue; } #endif ts = turnstile_trywait(&rw->lock_object); v = rw->rw_lock; #ifdef ADAPTIVE_RWLOCKS /* * The current lock owner might have started executing * on another CPU (or the lock could have changed * owners) while we were waiting on the turnstile * chain lock. If so, drop the turnstile lock and try * again. */ if (!(v & RW_LOCK_READ)) { owner = (struct thread *)RW_OWNER(v); if (TD_IS_RUNNING(owner)) { turnstile_cancel(ts); continue; } } #endif /* * Check for the waiters flags about this rwlock. * If the lock was released, without maintain any pending * waiters queue, simply try to acquire it. * If a pending waiters queue is present, claim the lock * ownership and maintain the pending queue. */ x = v & (RW_LOCK_WAITERS | RW_LOCK_WRITE_SPINNER); if ((v & ~x) == RW_UNLOCKED) { x &= ~RW_LOCK_WRITE_SPINNER; if (atomic_cmpset_acq_ptr(&rw->rw_lock, v, tid | x)) { if (x) turnstile_claim(ts); else turnstile_cancel(ts); break; } turnstile_cancel(ts); continue; } /* * If the RW_LOCK_WRITE_WAITERS flag isn't set, then try to * set it. If we fail to set it, then loop back and try * again. */ if (!(v & RW_LOCK_WRITE_WAITERS)) { if (!atomic_cmpset_ptr(&rw->rw_lock, v, v | RW_LOCK_WRITE_WAITERS)) { turnstile_cancel(ts); continue; } if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p set write waiters flag", __func__, rw); } /* * We were unable to acquire the lock and the write waiters * flag is set, so we must block on the turnstile. */ if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p blocking on turnstile", __func__, rw); #ifdef KDTRACE_HOOKS sleep_time -= lockstat_nsecs(); #endif turnstile_wait(ts, rw_owner(rw), TS_EXCLUSIVE_QUEUE); #ifdef KDTRACE_HOOKS sleep_time += lockstat_nsecs(); sleep_cnt++; #endif if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p resuming from turnstile", __func__, rw); #ifdef ADAPTIVE_RWLOCKS spintries = 0; #endif } LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_RW_WLOCK_ACQUIRE, rw, contested, waittime, file, line); #ifdef KDTRACE_HOOKS if (sleep_time) LOCKSTAT_RECORD1(LS_RW_WLOCK_BLOCK, rw, sleep_time); /* * Record only the loops spinning and not sleeping. */ if (spin_cnt > sleep_cnt) LOCKSTAT_RECORD1(LS_RW_WLOCK_SPIN, rw, (spin_cnt - sleep_cnt)); #endif } /* * This function is called if the first try at releasing a write lock failed. * This means that one of the 2 waiter bits must be set indicating that at * least one thread is waiting on this lock. */ void _rw_wunlock_hard(struct rwlock *rw, uintptr_t tid, const char *file, int line) { struct turnstile *ts; uintptr_t v; int queue; + if (SCHEDULER_STOPPED()) + return; + if (rw_wlocked(rw) && rw_recursed(rw)) { rw->rw_recurse--; if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p unrecursing", __func__, rw); return; } KASSERT(rw->rw_lock & (RW_LOCK_READ_WAITERS | RW_LOCK_WRITE_WAITERS), ("%s: neither of the waiter flags are set", __func__)); if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p contested", __func__, rw); turnstile_chain_lock(&rw->lock_object); ts = turnstile_lookup(&rw->lock_object); MPASS(ts != NULL); /* * Use the same algo as sx locks for now. Prefer waking up shared * waiters if we have any over writers. This is probably not ideal. * * 'v' is the value we are going to write back to rw_lock. If we * have waiters on both queues, we need to preserve the state of * the waiter flag for the queue we don't wake up. For now this is * hardcoded for the algorithm mentioned above. * * In the case of both readers and writers waiting we wakeup the * readers but leave the RW_LOCK_WRITE_WAITERS flag set. If a * new writer comes in before a reader it will claim the lock up * above. There is probably a potential priority inversion in * there that could be worked around either by waking both queues * of waiters or doing some complicated lock handoff gymnastics. */ v = RW_UNLOCKED; if (rw->rw_lock & RW_LOCK_WRITE_WAITERS) { queue = TS_EXCLUSIVE_QUEUE; v |= (rw->rw_lock & RW_LOCK_READ_WAITERS); } else queue = TS_SHARED_QUEUE; /* Wake up all waiters for the specific queue. */ if (LOCK_LOG_TEST(&rw->lock_object, 0)) CTR3(KTR_LOCK, "%s: %p waking up %s waiters", __func__, rw, queue == TS_SHARED_QUEUE ? "read" : "write"); turnstile_broadcast(ts, queue); atomic_store_rel_ptr(&rw->rw_lock, v); turnstile_unpend(ts, TS_EXCLUSIVE_LOCK); turnstile_chain_unlock(&rw->lock_object); } /* * Attempt to do a non-blocking upgrade from a read lock to a write * lock. This will only succeed if this thread holds a single read * lock. Returns true if the upgrade succeeded and false otherwise. */ int _rw_try_upgrade(struct rwlock *rw, const char *file, int line) { uintptr_t v, x, tid; struct turnstile *ts; int success; + if (SCHEDULER_STOPPED()) + return (1); + KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_try_upgrade() of destroyed rwlock @ %s:%d", file, line)); _rw_assert(rw, RA_RLOCKED, file, line); /* * Attempt to switch from one reader to a writer. If there * are any write waiters, then we will have to lock the * turnstile first to prevent races with another writer * calling turnstile_wait() before we have claimed this * turnstile. So, do the simple case of no waiters first. */ tid = (uintptr_t)curthread; success = 0; for (;;) { v = rw->rw_lock; if (RW_READERS(v) > 1) break; if (!(v & RW_LOCK_WAITERS)) { success = atomic_cmpset_ptr(&rw->rw_lock, v, tid); if (!success) continue; break; } /* * Ok, we think we have waiters, so lock the turnstile. */ ts = turnstile_trywait(&rw->lock_object); v = rw->rw_lock; if (RW_READERS(v) > 1) { turnstile_cancel(ts); break; } /* * Try to switch from one reader to a writer again. This time * we honor the current state of the waiters flags. * If we obtain the lock with the flags set, then claim * ownership of the turnstile. */ x = rw->rw_lock & RW_LOCK_WAITERS; success = atomic_cmpset_ptr(&rw->rw_lock, v, tid | x); if (success) { if (x) turnstile_claim(ts); else turnstile_cancel(ts); break; } turnstile_cancel(ts); } LOCK_LOG_TRY("WUPGRADE", &rw->lock_object, 0, success, file, line); if (success) { curthread->td_rw_rlocks--; WITNESS_UPGRADE(&rw->lock_object, LOP_EXCLUSIVE | LOP_TRYLOCK, file, line); LOCKSTAT_RECORD0(LS_RW_TRYUPGRADE_UPGRADE, rw); } return (success); } /* * Downgrade a write lock into a single read lock. */ void _rw_downgrade(struct rwlock *rw, const char *file, int line) { struct turnstile *ts; uintptr_t tid, v; int rwait, wwait; + + if (SCHEDULER_STOPPED()) + return; KASSERT(rw->rw_lock != RW_DESTROYED, ("rw_downgrade() of destroyed rwlock @ %s:%d", file, line)); _rw_assert(rw, RA_WLOCKED | RA_NOTRECURSED, file, line); #ifndef INVARIANTS if (rw_recursed(rw)) panic("downgrade of a recursed lock"); #endif WITNESS_DOWNGRADE(&rw->lock_object, 0, file, line); /* * Convert from a writer to a single reader. First we handle * the easy case with no waiters. If there are any waiters, we * lock the turnstile and "disown" the lock. */ tid = (uintptr_t)curthread; if (atomic_cmpset_rel_ptr(&rw->rw_lock, tid, RW_READERS_LOCK(1))) goto out; /* * Ok, we think we have waiters, so lock the turnstile so we can * read the waiter flags without any races. */ turnstile_chain_lock(&rw->lock_object); v = rw->rw_lock & RW_LOCK_WAITERS; rwait = v & RW_LOCK_READ_WAITERS; wwait = v & RW_LOCK_WRITE_WAITERS; MPASS(rwait | wwait); /* * Downgrade from a write lock while preserving waiters flag * and give up ownership of the turnstile. */ ts = turnstile_lookup(&rw->lock_object); MPASS(ts != NULL); if (!wwait) v &= ~RW_LOCK_READ_WAITERS; atomic_store_rel_ptr(&rw->rw_lock, RW_READERS_LOCK(1) | v); /* * Wake other readers if there are no writers pending. Otherwise they * won't be able to acquire the lock anyway. */ if (rwait && !wwait) { turnstile_broadcast(ts, TS_SHARED_QUEUE); turnstile_unpend(ts, TS_EXCLUSIVE_LOCK); } else turnstile_disown(ts); turnstile_chain_unlock(&rw->lock_object); out: curthread->td_rw_rlocks++; LOCK_LOG_LOCK("WDOWNGRADE", &rw->lock_object, 0, 0, file, line); LOCKSTAT_RECORD0(LS_RW_DOWNGRADE_DOWNGRADE, rw); } #ifdef INVARIANT_SUPPORT #ifndef INVARIANTS #undef _rw_assert #endif /* * In the non-WITNESS case, rw_assert() can only detect that at least * *some* thread owns an rlock, but it cannot guarantee that *this* * thread owns an rlock. */ void _rw_assert(const struct rwlock *rw, int what, const char *file, int line) { if (panicstr != NULL) return; switch (what) { case RA_LOCKED: case RA_LOCKED | RA_RECURSED: case RA_LOCKED | RA_NOTRECURSED: case RA_RLOCKED: #ifdef WITNESS witness_assert(&rw->lock_object, what, file, line); #else /* * If some other thread has a write lock or we have one * and are asserting a read lock, fail. Also, if no one * has a lock at all, fail. */ if (rw->rw_lock == RW_UNLOCKED || (!(rw->rw_lock & RW_LOCK_READ) && (what == RA_RLOCKED || rw_wowner(rw) != curthread))) panic("Lock %s not %slocked @ %s:%d\n", rw->lock_object.lo_name, (what == RA_RLOCKED) ? "read " : "", file, line); if (!(rw->rw_lock & RW_LOCK_READ)) { if (rw_recursed(rw)) { if (what & RA_NOTRECURSED) panic("Lock %s recursed @ %s:%d\n", rw->lock_object.lo_name, file, line); } else if (what & RA_RECURSED) panic("Lock %s not recursed @ %s:%d\n", rw->lock_object.lo_name, file, line); } #endif break; case RA_WLOCKED: case RA_WLOCKED | RA_RECURSED: case RA_WLOCKED | RA_NOTRECURSED: if (rw_wowner(rw) != curthread) panic("Lock %s not exclusively locked @ %s:%d\n", rw->lock_object.lo_name, file, line); if (rw_recursed(rw)) { if (what & RA_NOTRECURSED) panic("Lock %s recursed @ %s:%d\n", rw->lock_object.lo_name, file, line); } else if (what & RA_RECURSED) panic("Lock %s not recursed @ %s:%d\n", rw->lock_object.lo_name, file, line); break; case RA_UNLOCKED: #ifdef WITNESS witness_assert(&rw->lock_object, what, file, line); #else /* * If we hold a write lock fail. We can't reliably check * to see if we hold a read lock or not. */ if (rw_wowner(rw) == curthread) panic("Lock %s exclusively locked @ %s:%d\n", rw->lock_object.lo_name, file, line); #endif break; default: panic("Unknown rw lock assertion: %d @ %s:%d", what, file, line); } } #endif /* INVARIANT_SUPPORT */ #ifdef DDB void db_show_rwlock(const struct lock_object *lock) { const struct rwlock *rw; struct thread *td; rw = (const struct rwlock *)lock; db_printf(" state: "); if (rw->rw_lock == RW_UNLOCKED) db_printf("UNLOCKED\n"); else if (rw->rw_lock == RW_DESTROYED) { db_printf("DESTROYED\n"); return; } else if (rw->rw_lock & RW_LOCK_READ) db_printf("RLOCK: %ju locks\n", (uintmax_t)(RW_READERS(rw->rw_lock))); else { td = rw_wowner(rw); db_printf("WLOCK: %p (tid %d, pid %d, \"%s\")\n", td, td->td_tid, td->td_proc->p_pid, td->td_name); if (rw_recursed(rw)) db_printf(" recursed: %u\n", rw->rw_recurse); } db_printf(" waiters: "); switch (rw->rw_lock & (RW_LOCK_READ_WAITERS | RW_LOCK_WRITE_WAITERS)) { case RW_LOCK_READ_WAITERS: db_printf("readers\n"); break; case RW_LOCK_WRITE_WAITERS: db_printf("writers\n"); break; case RW_LOCK_READ_WAITERS | RW_LOCK_WRITE_WAITERS: db_printf("readers and writers\n"); break; default: db_printf("none\n"); break; } } #endif Index: head/sys/kern/kern_shutdown.c =================================================================== --- head/sys/kern/kern_shutdown.c (revision 228423) +++ head/sys/kern/kern_shutdown.c (revision 228424) @@ -1,736 +1,766 @@ /*- * Copyright (c) 1986, 1988, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)kern_shutdown.c 8.3 (Berkeley) 1/21/94 */ #include __FBSDID("$FreeBSD$"); #include "opt_ddb.h" #include "opt_kdb.h" #include "opt_panic.h" #include "opt_sched.h" #include "opt_watchdog.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef SW_WATCHDOG #include #endif #include #include #include #include #include #include #include #include #include #include #include #ifndef PANIC_REBOOT_WAIT_TIME #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */ #endif /* * Note that stdarg.h and the ANSI style va_start macro is used for both * ANSI and traditional C compilers. */ #include #ifdef KDB #ifdef KDB_UNATTENDED int debugger_on_panic = 0; #else int debugger_on_panic = 1; #endif SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic, CTLFLAG_RW | CTLFLAG_TUN, &debugger_on_panic, 0, "Run debugger on kernel panic"); TUNABLE_INT("debug.debugger_on_panic", &debugger_on_panic); #ifdef KDB_TRACE static int trace_on_panic = 1; #else static int trace_on_panic = 0; #endif SYSCTL_INT(_debug, OID_AUTO, trace_on_panic, CTLFLAG_RW | CTLFLAG_TUN, &trace_on_panic, 0, "Print stack trace on kernel panic"); TUNABLE_INT("debug.trace_on_panic", &trace_on_panic); #endif /* KDB */ static int sync_on_panic = 0; SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW | CTLFLAG_TUN, &sync_on_panic, 0, "Do a sync before rebooting from a panic"); TUNABLE_INT("kern.sync_on_panic", &sync_on_panic); +static int stop_scheduler_on_panic = 0; +SYSCTL_INT(_kern, OID_AUTO, stop_scheduler_on_panic, CTLFLAG_RW | CTLFLAG_TUN, + &stop_scheduler_on_panic, 0, "stop scheduler upon entering panic"); +TUNABLE_INT("kern.stop_scheduler_on_panic", &stop_scheduler_on_panic); + static SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0, "Shutdown environment"); #ifndef DIAGNOSTIC static int show_busybufs; #else static int show_busybufs = 1; #endif SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW, &show_busybufs, 0, ""); /* * Variable panicstr contains argument to first call to panic; used as flag * to indicate that the kernel has already called panic. */ const char *panicstr; +int stop_scheduler; /* system stopped CPUs for panic */ int dumping; /* system is dumping */ int rebooting; /* system is rebooting */ static struct dumperinfo dumper; /* our selected dumper */ /* Context information for dump-debuggers. */ static struct pcb dumppcb; /* Registers. */ static lwpid_t dumptid; /* Thread ID. */ static void poweroff_wait(void *, int); static void shutdown_halt(void *junk, int howto); static void shutdown_panic(void *junk, int howto); static void shutdown_reset(void *junk, int howto); /* register various local shutdown events */ static void shutdown_conf(void *unused) { EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL, SHUTDOWN_PRI_FIRST); EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL, SHUTDOWN_PRI_LAST + 100); EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL, SHUTDOWN_PRI_LAST + 100); EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL, SHUTDOWN_PRI_LAST + 200); } SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL); /* * The system call that results in a reboot. */ /* ARGSUSED */ int sys_reboot(struct thread *td, struct reboot_args *uap) { int error; error = 0; #ifdef MAC error = mac_system_check_reboot(td->td_ucred, uap->opt); #endif if (error == 0) error = priv_check(td, PRIV_REBOOT); if (error == 0) { mtx_lock(&Giant); kern_reboot(uap->opt); mtx_unlock(&Giant); } return (error); } /* * Called by events that want to shut down.. e.g on a PC */ static int shutdown_howto = 0; void shutdown_nice(int howto) { shutdown_howto = howto; /* Send a signal to init(8) and have it shutdown the world */ if (initproc != NULL) { PROC_LOCK(initproc); kern_psignal(initproc, SIGINT); PROC_UNLOCK(initproc); } else { /* No init(8) running, so simply reboot */ kern_reboot(RB_NOSYNC); } return; } static int waittime = -1; static void print_uptime(void) { int f; struct timespec ts; getnanouptime(&ts); printf("Uptime: "); f = 0; if (ts.tv_sec >= 86400) { printf("%ldd", (long)ts.tv_sec / 86400); ts.tv_sec %= 86400; f = 1; } if (f || ts.tv_sec >= 3600) { printf("%ldh", (long)ts.tv_sec / 3600); ts.tv_sec %= 3600; f = 1; } if (f || ts.tv_sec >= 60) { printf("%ldm", (long)ts.tv_sec / 60); ts.tv_sec %= 60; f = 1; } printf("%lds\n", (long)ts.tv_sec); } int doadump(boolean_t textdump) { boolean_t coredump; if (dumping) return (EBUSY); if (dumper.dumper == NULL) return (ENXIO); savectx(&dumppcb); dumptid = curthread->td_tid; dumping++; coredump = TRUE; #ifdef DDB if (textdump && textdump_pending) { coredump = FALSE; textdump_dumpsys(&dumper); } #endif if (coredump) dumpsys(&dumper); dumping--; return (0); } static int isbufbusy(struct buf *bp) { if (((bp->b_flags & (B_INVAL | B_PERSISTENT)) == 0 && BUF_ISLOCKED(bp)) || ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI)) return (1); return (0); } /* * Shutdown the system cleanly to prepare for reboot, halt, or power off. */ void kern_reboot(int howto) { static int first_buf_printf = 1; #if defined(SMP) /* * Bind us to CPU 0 so that all shutdown code runs there. Some * systems don't shutdown properly (i.e., ACPI power off) if we * run on another processor. */ - thread_lock(curthread); - sched_bind(curthread, 0); - thread_unlock(curthread); - KASSERT(PCPU_GET(cpuid) == 0, ("%s: not running on cpu 0", __func__)); + if (!SCHEDULER_STOPPED()) { + thread_lock(curthread); + sched_bind(curthread, 0); + thread_unlock(curthread); + KASSERT(PCPU_GET(cpuid) == 0, ("boot: not running on cpu 0")); + } #endif /* We're in the process of rebooting. */ rebooting = 1; /* collect extra flags that shutdown_nice might have set */ howto |= shutdown_howto; /* We are out of the debugger now. */ kdb_active = 0; /* * Do any callouts that should be done BEFORE syncing the filesystems. */ EVENTHANDLER_INVOKE(shutdown_pre_sync, howto); /* * Now sync filesystems */ if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) { register struct buf *bp; int iter, nbusy, pbusy; #ifndef PREEMPTION int subiter; #endif waittime = 0; #ifdef SW_WATCHDOG wdog_kern_pat(WD_LASTVAL); #endif sys_sync(curthread, NULL); /* * With soft updates, some buffers that are * written will be remarked as dirty until other * buffers are written. */ for (iter = pbusy = 0; iter < 20; iter++) { nbusy = 0; for (bp = &buf[nbuf]; --bp >= buf; ) if (isbufbusy(bp)) nbusy++; if (nbusy == 0) { if (first_buf_printf) printf("All buffers synced."); break; } if (first_buf_printf) { printf("Syncing disks, buffers remaining... "); first_buf_printf = 0; } printf("%d ", nbusy); if (nbusy < pbusy) iter = 0; pbusy = nbusy; #ifdef SW_WATCHDOG wdog_kern_pat(WD_LASTVAL); #endif sys_sync(curthread, NULL); #ifdef PREEMPTION /* * Drop Giant and spin for a while to allow * interrupt threads to run. */ DROP_GIANT(); DELAY(50000 * iter); PICKUP_GIANT(); #else /* * Drop Giant and context switch several times to * allow interrupt threads to run. */ DROP_GIANT(); for (subiter = 0; subiter < 50 * iter; subiter++) { thread_lock(curthread); mi_switch(SW_VOL, NULL); thread_unlock(curthread); DELAY(1000); } PICKUP_GIANT(); #endif } printf("\n"); /* * Count only busy local buffers to prevent forcing * a fsck if we're just a client of a wedged NFS server */ nbusy = 0; for (bp = &buf[nbuf]; --bp >= buf; ) { if (isbufbusy(bp)) { #if 0 /* XXX: This is bogus. We should probably have a BO_REMOTE flag instead */ if (bp->b_dev == NULL) { TAILQ_REMOVE(&mountlist, bp->b_vp->v_mount, mnt_list); continue; } #endif nbusy++; if (show_busybufs > 0) { printf( "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:", nbusy, bp, bp->b_vp, bp->b_flags, (intmax_t)bp->b_blkno, (intmax_t)bp->b_lblkno); BUF_LOCKPRINTINFO(bp); if (show_busybufs > 1) vn_printf(bp->b_vp, "vnode content: "); } } } if (nbusy) { /* * Failed to sync all blocks. Indicate this and don't * unmount filesystems (thus forcing an fsck on reboot). */ printf("Giving up on %d buffers\n", nbusy); DELAY(5000000); /* 5 seconds */ } else { if (!first_buf_printf) printf("Final sync complete\n"); /* * Unmount filesystems */ if (panicstr == 0) vfs_unmountall(); } swapoff_all(); DELAY(100000); /* wait for console output to finish */ } print_uptime(); /* * Ok, now do things that assume all filesystem activity has * been completed. */ EVENTHANDLER_INVOKE(shutdown_post_sync, howto); if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold && !dumping) doadump(TRUE); /* Now that we're going to really halt the system... */ EVENTHANDLER_INVOKE(shutdown_final, howto); for(;;) ; /* safety against shutdown_reset not working */ /* NOTREACHED */ } /* * If the shutdown was a clean halt, behave accordingly. */ static void shutdown_halt(void *junk, int howto) { if (howto & RB_HALT) { printf("\n"); printf("The operating system has halted.\n"); printf("Please press any key to reboot.\n\n"); switch (cngetc()) { case -1: /* No console, just die */ cpu_halt(); /* NOTREACHED */ default: howto &= ~RB_HALT; break; } } } /* * Check to see if the system paniced, pause and then reboot * according to the specified delay. */ static void shutdown_panic(void *junk, int howto) { int loop; if (howto & RB_DUMP) { if (PANIC_REBOOT_WAIT_TIME != 0) { if (PANIC_REBOOT_WAIT_TIME != -1) { printf("Automatic reboot in %d seconds - " "press a key on the console to abort\n", PANIC_REBOOT_WAIT_TIME); for (loop = PANIC_REBOOT_WAIT_TIME * 10; loop > 0; --loop) { DELAY(1000 * 100); /* 1/10th second */ /* Did user type a key? */ if (cncheckc() != -1) break; } if (!loop) return; } } else { /* zero time specified - reboot NOW */ return; } printf("--> Press a key on the console to reboot,\n"); printf("--> or switch off the system now.\n"); cngetc(); } } /* * Everything done, now reset */ static void shutdown_reset(void *junk, int howto) { printf("Rebooting...\n"); DELAY(1000000); /* wait 1 sec for printf's to complete and be read */ /* * Acquiring smp_ipi_mtx here has a double effect: * - it disables interrupts avoiding CPU0 preemption * by fast handlers (thus deadlocking against other CPUs) * - it avoids deadlocks against smp_rendezvous() or, more * generally, threads busy-waiting, with this spinlock held, * and waiting for responses by threads on other CPUs * (ie. smp_tlb_shootdown()). * * For the !SMP case it just needs to handle the former problem. */ #ifdef SMP mtx_lock_spin(&smp_ipi_mtx); #else spinlock_enter(); #endif /* cpu_boot(howto); */ /* doesn't do anything at the moment */ cpu_reset(); /* NOTREACHED */ /* assuming reset worked */ } /* * Panic is called on unresolvable fatal errors. It prints "panic: mesg", * and then reboots. If we are called twice, then we avoid trying to sync * the disks as this often leads to recursive panics. */ void panic(const char *fmt, ...) { #ifdef SMP static volatile u_int panic_cpu = NOCPU; + cpuset_t other_cpus; #endif struct thread *td = curthread; int bootopt, newpanic; va_list ap; static char buf[256]; - critical_enter(); + if (stop_scheduler_on_panic) + spinlock_enter(); + else + critical_enter(); + #ifdef SMP /* * We don't want multiple CPU's to panic at the same time, so we * use panic_cpu as a simple spinlock. We have to keep checking * panic_cpu if we are spinning in case the panic on the first * CPU is canceled. */ if (panic_cpu != PCPU_GET(cpuid)) while (atomic_cmpset_int(&panic_cpu, NOCPU, PCPU_GET(cpuid)) == 0) while (panic_cpu != NOCPU) ; /* nothing */ + + if (stop_scheduler_on_panic) { + if (panicstr == NULL && !kdb_active) { + other_cpus = all_cpus; + CPU_CLR(PCPU_GET(cpuid), &other_cpus); + stop_cpus_hard(other_cpus); + } + + /* + * We set stop_scheduler here and not in the block above, + * because we want to ensure that if panic has been called and + * stop_scheduler_on_panic is true, then stop_scheduler will + * always be set. Even if panic has been entered from kdb. + */ + stop_scheduler = 1; + } #endif bootopt = RB_AUTOBOOT; newpanic = 0; if (panicstr) bootopt |= RB_NOSYNC; else { bootopt |= RB_DUMP; panicstr = fmt; newpanic = 1; } va_start(ap, fmt); if (newpanic) { (void)vsnprintf(buf, sizeof(buf), fmt, ap); panicstr = buf; printf("panic: %s\n", buf); } else { printf("panic: "); vprintf(fmt, ap); printf("\n"); } va_end(ap); #ifdef SMP printf("cpuid = %d\n", PCPU_GET(cpuid)); #endif #ifdef KDB if (newpanic && trace_on_panic) kdb_backtrace(); if (debugger_on_panic) kdb_enter(KDB_WHY_PANIC, "panic"); #endif /*thread_lock(td); */ td->td_flags |= TDF_INPANIC; /* thread_unlock(td); */ if (!sync_on_panic) bootopt |= RB_NOSYNC; - critical_exit(); + if (!stop_scheduler_on_panic) + critical_exit(); kern_reboot(bootopt); } /* * Support for poweroff delay. * * Please note that setting this delay too short might power off your machine * before the write cache on your hard disk has been flushed, leading to * soft-updates inconsistencies. */ #ifndef POWEROFF_DELAY # define POWEROFF_DELAY 5000 #endif static int poweroff_delay = POWEROFF_DELAY; SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW, &poweroff_delay, 0, ""); static void poweroff_wait(void *junk, int howto) { if (!(howto & RB_POWEROFF) || poweroff_delay <= 0) return; DELAY(poweroff_delay * 1000); } /* * Some system processes (e.g. syncer) need to be stopped at appropriate * points in their main loops prior to a system shutdown, so that they * won't interfere with the shutdown process (e.g. by holding a disk buf * to cause sync to fail). For each of these system processes, register * shutdown_kproc() as a handler for one of shutdown events. */ static int kproc_shutdown_wait = 60; SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW, &kproc_shutdown_wait, 0, ""); void kproc_shutdown(void *arg, int howto) { struct proc *p; int error; if (panicstr) return; p = (struct proc *)arg; printf("Waiting (max %d seconds) for system process `%s' to stop...", kproc_shutdown_wait, p->p_comm); error = kproc_suspend(p, kproc_shutdown_wait * hz); if (error == EWOULDBLOCK) printf("timed out\n"); else printf("done\n"); } void kthread_shutdown(void *arg, int howto) { struct thread *td; int error; if (panicstr) return; td = (struct thread *)arg; printf("Waiting (max %d seconds) for system thread `%s' to stop...", kproc_shutdown_wait, td->td_name); error = kthread_suspend(td, kproc_shutdown_wait * hz); if (error == EWOULDBLOCK) printf("timed out\n"); else printf("done\n"); } /* Registration of dumpers */ int set_dumper(struct dumperinfo *di) { if (di == NULL) { bzero(&dumper, sizeof dumper); return (0); } if (dumper.dumper != NULL) return (EBUSY); dumper = *di; return (0); } /* Call dumper with bounds checking. */ int dump_write(struct dumperinfo *di, void *virtual, vm_offset_t physical, off_t offset, size_t length) { if (length != 0 && (offset < di->mediaoffset || offset - di->mediaoffset + length > di->mediasize)) { printf("Attempt to write outside dump device boundaries.\n" "offset(%jd), mediaoffset(%jd), length(%ju), mediasize(%jd).\n", (intmax_t)offset, (intmax_t)di->mediaoffset, (uintmax_t)length, (intmax_t)di->mediasize); return (ENOSPC); } return (di->dumper(di->priv, virtual, physical, offset, length)); } void mkdumpheader(struct kerneldumpheader *kdh, char *magic, uint32_t archver, uint64_t dumplen, uint32_t blksz) { bzero(kdh, sizeof(*kdh)); strncpy(kdh->magic, magic, sizeof(kdh->magic)); strncpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture)); kdh->version = htod32(KERNELDUMPVERSION); kdh->architectureversion = htod32(archver); kdh->dumplength = htod64(dumplen); kdh->dumptime = htod64(time_second); kdh->blocksize = htod32(blksz); strncpy(kdh->hostname, prison0.pr_hostname, sizeof(kdh->hostname)); strncpy(kdh->versionstring, version, sizeof(kdh->versionstring)); if (panicstr != NULL) strncpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring)); kdh->parity = kerneldump_parity(kdh); } Index: head/sys/kern/kern_sx.c =================================================================== --- head/sys/kern/kern_sx.c (revision 228423) +++ head/sys/kern/kern_sx.c (revision 228424) @@ -1,1161 +1,1193 @@ /*- * Copyright (c) 2007 Attilio Rao * Copyright (c) 2001 Jason Evans * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice(s), this list of conditions and the following disclaimer as * the first lines of this file unmodified other than the possible * addition of one or more copyright notices. * 2. Redistributions in binary form must reproduce the above copyright * notice(s), this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH * DAMAGE. */ /* * Shared/exclusive locks. This implementation attempts to ensure * deterministic lock granting behavior, so that slocks and xlocks are * interleaved. * * Priority propagation will not generally raise the priority of lock holders, * so should not be relied upon in combination with sx locks. */ #include "opt_ddb.h" #include "opt_kdtrace.h" #include "opt_no_adaptive_sx.h" #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #if defined(SMP) && !defined(NO_ADAPTIVE_SX) #include #endif #ifdef DDB #include #endif #if defined(SMP) && !defined(NO_ADAPTIVE_SX) #define ADAPTIVE_SX #endif CTASSERT((SX_NOADAPTIVE & LO_CLASSFLAGS) == SX_NOADAPTIVE); /* Handy macros for sleep queues. */ #define SQ_EXCLUSIVE_QUEUE 0 #define SQ_SHARED_QUEUE 1 /* * Variations on DROP_GIANT()/PICKUP_GIANT() for use in this file. We * drop Giant anytime we have to sleep or if we adaptively spin. */ #define GIANT_DECLARE \ int _giantcnt = 0; \ WITNESS_SAVE_DECL(Giant) \ #define GIANT_SAVE() do { \ if (mtx_owned(&Giant)) { \ WITNESS_SAVE(&Giant.lock_object, Giant); \ while (mtx_owned(&Giant)) { \ _giantcnt++; \ mtx_unlock(&Giant); \ } \ } \ } while (0) #define GIANT_RESTORE() do { \ if (_giantcnt > 0) { \ mtx_assert(&Giant, MA_NOTOWNED); \ while (_giantcnt--) \ mtx_lock(&Giant); \ WITNESS_RESTORE(&Giant.lock_object, Giant); \ } \ } while (0) /* * Returns true if an exclusive lock is recursed. It assumes * curthread currently has an exclusive lock. */ #define sx_recurse lock_object.lo_data #define sx_recursed(sx) ((sx)->sx_recurse != 0) static void assert_sx(const struct lock_object *lock, int what); #ifdef DDB static void db_show_sx(const struct lock_object *lock); #endif static void lock_sx(struct lock_object *lock, int how); #ifdef KDTRACE_HOOKS static int owner_sx(const struct lock_object *lock, struct thread **owner); #endif static int unlock_sx(struct lock_object *lock); struct lock_class lock_class_sx = { .lc_name = "sx", .lc_flags = LC_SLEEPLOCK | LC_SLEEPABLE | LC_RECURSABLE | LC_UPGRADABLE, .lc_assert = assert_sx, #ifdef DDB .lc_ddb_show = db_show_sx, #endif .lc_lock = lock_sx, .lc_unlock = unlock_sx, #ifdef KDTRACE_HOOKS .lc_owner = owner_sx, #endif }; #ifndef INVARIANTS #define _sx_assert(sx, what, file, line) #endif #ifdef ADAPTIVE_SX static u_int asx_retries = 10; static u_int asx_loops = 10000; static SYSCTL_NODE(_debug, OID_AUTO, sx, CTLFLAG_RD, NULL, "sxlock debugging"); SYSCTL_UINT(_debug_sx, OID_AUTO, retries, CTLFLAG_RW, &asx_retries, 0, ""); SYSCTL_UINT(_debug_sx, OID_AUTO, loops, CTLFLAG_RW, &asx_loops, 0, ""); #endif void assert_sx(const struct lock_object *lock, int what) { sx_assert((const struct sx *)lock, what); } void lock_sx(struct lock_object *lock, int how) { struct sx *sx; sx = (struct sx *)lock; if (how) sx_xlock(sx); else sx_slock(sx); } int unlock_sx(struct lock_object *lock) { struct sx *sx; sx = (struct sx *)lock; sx_assert(sx, SA_LOCKED | SA_NOTRECURSED); if (sx_xlocked(sx)) { sx_xunlock(sx); return (1); } else { sx_sunlock(sx); return (0); } } #ifdef KDTRACE_HOOKS int owner_sx(const struct lock_object *lock, struct thread **owner) { const struct sx *sx = (const struct sx *)lock; uintptr_t x = sx->sx_lock; *owner = (struct thread *)SX_OWNER(x); return ((x & SX_LOCK_SHARED) != 0 ? (SX_SHARERS(x) != 0) : (*owner != NULL)); } #endif void sx_sysinit(void *arg) { struct sx_args *sargs = arg; sx_init_flags(sargs->sa_sx, sargs->sa_desc, sargs->sa_flags); } void sx_init_flags(struct sx *sx, const char *description, int opts) { int flags; MPASS((opts & ~(SX_QUIET | SX_RECURSE | SX_NOWITNESS | SX_DUPOK | SX_NOPROFILE | SX_NOADAPTIVE)) == 0); ASSERT_ATOMIC_LOAD_PTR(sx->sx_lock, ("%s: sx_lock not aligned for %s: %p", __func__, description, &sx->sx_lock)); flags = LO_SLEEPABLE | LO_UPGRADABLE; if (opts & SX_DUPOK) flags |= LO_DUPOK; if (opts & SX_NOPROFILE) flags |= LO_NOPROFILE; if (!(opts & SX_NOWITNESS)) flags |= LO_WITNESS; if (opts & SX_RECURSE) flags |= LO_RECURSABLE; if (opts & SX_QUIET) flags |= LO_QUIET; flags |= opts & SX_NOADAPTIVE; sx->sx_lock = SX_LOCK_UNLOCKED; sx->sx_recurse = 0; lock_init(&sx->lock_object, &lock_class_sx, description, NULL, flags); } void sx_destroy(struct sx *sx) { KASSERT(sx->sx_lock == SX_LOCK_UNLOCKED, ("sx lock still held")); KASSERT(sx->sx_recurse == 0, ("sx lock still recursed")); sx->sx_lock = SX_LOCK_DESTROYED; lock_destroy(&sx->lock_object); } int _sx_slock(struct sx *sx, int opts, const char *file, int line) { int error = 0; + if (SCHEDULER_STOPPED()) + return (0); MPASS(curthread != NULL); KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_slock() of destroyed sx @ %s:%d", file, line)); WITNESS_CHECKORDER(&sx->lock_object, LOP_NEWORDER, file, line, NULL); error = __sx_slock(sx, opts, file, line); if (!error) { LOCK_LOG_LOCK("SLOCK", &sx->lock_object, 0, 0, file, line); WITNESS_LOCK(&sx->lock_object, 0, file, line); curthread->td_locks++; } return (error); } int sx_try_slock_(struct sx *sx, const char *file, int line) { uintptr_t x; + if (SCHEDULER_STOPPED()) + return (1); + for (;;) { x = sx->sx_lock; KASSERT(x != SX_LOCK_DESTROYED, ("sx_try_slock() of destroyed sx @ %s:%d", file, line)); if (!(x & SX_LOCK_SHARED)) break; if (atomic_cmpset_acq_ptr(&sx->sx_lock, x, x + SX_ONE_SHARER)) { LOCK_LOG_TRY("SLOCK", &sx->lock_object, 0, 1, file, line); WITNESS_LOCK(&sx->lock_object, LOP_TRYLOCK, file, line); curthread->td_locks++; return (1); } } LOCK_LOG_TRY("SLOCK", &sx->lock_object, 0, 0, file, line); return (0); } int _sx_xlock(struct sx *sx, int opts, const char *file, int line) { int error = 0; + if (SCHEDULER_STOPPED()) + return (0); MPASS(curthread != NULL); KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_xlock() of destroyed sx @ %s:%d", file, line)); WITNESS_CHECKORDER(&sx->lock_object, LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); error = __sx_xlock(sx, curthread, opts, file, line); if (!error) { LOCK_LOG_LOCK("XLOCK", &sx->lock_object, 0, sx->sx_recurse, file, line); WITNESS_LOCK(&sx->lock_object, LOP_EXCLUSIVE, file, line); curthread->td_locks++; } return (error); } int sx_try_xlock_(struct sx *sx, const char *file, int line) { int rval; + if (SCHEDULER_STOPPED()) + return (1); + MPASS(curthread != NULL); KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_try_xlock() of destroyed sx @ %s:%d", file, line)); if (sx_xlocked(sx) && (sx->lock_object.lo_flags & LO_RECURSABLE) != 0) { sx->sx_recurse++; atomic_set_ptr(&sx->sx_lock, SX_LOCK_RECURSED); rval = 1; } else rval = atomic_cmpset_acq_ptr(&sx->sx_lock, SX_LOCK_UNLOCKED, (uintptr_t)curthread); LOCK_LOG_TRY("XLOCK", &sx->lock_object, 0, rval, file, line); if (rval) { WITNESS_LOCK(&sx->lock_object, LOP_EXCLUSIVE | LOP_TRYLOCK, file, line); curthread->td_locks++; } return (rval); } void _sx_sunlock(struct sx *sx, const char *file, int line) { + if (SCHEDULER_STOPPED()) + return; MPASS(curthread != NULL); KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_sunlock() of destroyed sx @ %s:%d", file, line)); _sx_assert(sx, SA_SLOCKED, file, line); curthread->td_locks--; WITNESS_UNLOCK(&sx->lock_object, 0, file, line); LOCK_LOG_LOCK("SUNLOCK", &sx->lock_object, 0, 0, file, line); __sx_sunlock(sx, file, line); LOCKSTAT_PROFILE_RELEASE_LOCK(LS_SX_SUNLOCK_RELEASE, sx); } void _sx_xunlock(struct sx *sx, const char *file, int line) { + if (SCHEDULER_STOPPED()) + return; MPASS(curthread != NULL); KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_xunlock() of destroyed sx @ %s:%d", file, line)); _sx_assert(sx, SA_XLOCKED, file, line); curthread->td_locks--; WITNESS_UNLOCK(&sx->lock_object, LOP_EXCLUSIVE, file, line); LOCK_LOG_LOCK("XUNLOCK", &sx->lock_object, 0, sx->sx_recurse, file, line); if (!sx_recursed(sx)) LOCKSTAT_PROFILE_RELEASE_LOCK(LS_SX_XUNLOCK_RELEASE, sx); __sx_xunlock(sx, curthread, file, line); } /* * Try to do a non-blocking upgrade from a shared lock to an exclusive lock. * This will only succeed if this thread holds a single shared lock. * Return 1 if if the upgrade succeed, 0 otherwise. */ int sx_try_upgrade_(struct sx *sx, const char *file, int line) { uintptr_t x; int success; + if (SCHEDULER_STOPPED()) + return (1); + KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_try_upgrade() of destroyed sx @ %s:%d", file, line)); _sx_assert(sx, SA_SLOCKED, file, line); /* * Try to switch from one shared lock to an exclusive lock. We need * to maintain the SX_LOCK_EXCLUSIVE_WAITERS flag if set so that * we will wake up the exclusive waiters when we drop the lock. */ x = sx->sx_lock & SX_LOCK_EXCLUSIVE_WAITERS; success = atomic_cmpset_ptr(&sx->sx_lock, SX_SHARERS_LOCK(1) | x, (uintptr_t)curthread | x); LOCK_LOG_TRY("XUPGRADE", &sx->lock_object, 0, success, file, line); if (success) { WITNESS_UPGRADE(&sx->lock_object, LOP_EXCLUSIVE | LOP_TRYLOCK, file, line); LOCKSTAT_RECORD0(LS_SX_TRYUPGRADE_UPGRADE, sx); } return (success); } /* * Downgrade an unrecursed exclusive lock into a single shared lock. */ void sx_downgrade_(struct sx *sx, const char *file, int line) { uintptr_t x; int wakeup_swapper; + if (SCHEDULER_STOPPED()) + return; + KASSERT(sx->sx_lock != SX_LOCK_DESTROYED, ("sx_downgrade() of destroyed sx @ %s:%d", file, line)); _sx_assert(sx, SA_XLOCKED | SA_NOTRECURSED, file, line); #ifndef INVARIANTS if (sx_recursed(sx)) panic("downgrade of a recursed lock"); #endif WITNESS_DOWNGRADE(&sx->lock_object, 0, file, line); /* * Try to switch from an exclusive lock with no shared waiters * to one sharer with no shared waiters. If there are * exclusive waiters, we don't need to lock the sleep queue so * long as we preserve the flag. We do one quick try and if * that fails we grab the sleepq lock to keep the flags from * changing and do it the slow way. * * We have to lock the sleep queue if there are shared waiters * so we can wake them up. */ x = sx->sx_lock; if (!(x & SX_LOCK_SHARED_WAITERS) && atomic_cmpset_rel_ptr(&sx->sx_lock, x, SX_SHARERS_LOCK(1) | (x & SX_LOCK_EXCLUSIVE_WAITERS))) { LOCK_LOG_LOCK("XDOWNGRADE", &sx->lock_object, 0, 0, file, line); return; } /* * Lock the sleep queue so we can read the waiters bits * without any races and wakeup any shared waiters. */ sleepq_lock(&sx->lock_object); /* * Preserve SX_LOCK_EXCLUSIVE_WAITERS while downgraded to a single * shared lock. If there are any shared waiters, wake them up. */ wakeup_swapper = 0; x = sx->sx_lock; atomic_store_rel_ptr(&sx->sx_lock, SX_SHARERS_LOCK(1) | (x & SX_LOCK_EXCLUSIVE_WAITERS)); if (x & SX_LOCK_SHARED_WAITERS) wakeup_swapper = sleepq_broadcast(&sx->lock_object, SLEEPQ_SX, 0, SQ_SHARED_QUEUE); sleepq_release(&sx->lock_object); LOCK_LOG_LOCK("XDOWNGRADE", &sx->lock_object, 0, 0, file, line); LOCKSTAT_RECORD0(LS_SX_DOWNGRADE_DOWNGRADE, sx); if (wakeup_swapper) kick_proc0(); } /* * This function represents the so-called 'hard case' for sx_xlock * operation. All 'easy case' failures are redirected to this. Note * that ideally this would be a static function, but it needs to be * accessible from at least sx.h. */ int _sx_xlock_hard(struct sx *sx, uintptr_t tid, int opts, const char *file, int line) { GIANT_DECLARE; #ifdef ADAPTIVE_SX volatile struct thread *owner; u_int i, spintries = 0; #endif uintptr_t x; #ifdef LOCK_PROFILING uint64_t waittime = 0; int contested = 0; #endif int error = 0; #ifdef KDTRACE_HOOKS uint64_t spin_cnt = 0; uint64_t sleep_cnt = 0; int64_t sleep_time = 0; #endif + if (SCHEDULER_STOPPED()) + return (0); + /* If we already hold an exclusive lock, then recurse. */ if (sx_xlocked(sx)) { KASSERT((sx->lock_object.lo_flags & LO_RECURSABLE) != 0, ("_sx_xlock_hard: recursed on non-recursive sx %s @ %s:%d\n", sx->lock_object.lo_name, file, line)); sx->sx_recurse++; atomic_set_ptr(&sx->sx_lock, SX_LOCK_RECURSED); if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p recursing", __func__, sx); return (0); } if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR5(KTR_LOCK, "%s: %s contested (lock=%p) at %s:%d", __func__, sx->lock_object.lo_name, (void *)sx->sx_lock, file, line); while (!atomic_cmpset_acq_ptr(&sx->sx_lock, SX_LOCK_UNLOCKED, tid)) { #ifdef KDTRACE_HOOKS spin_cnt++; #endif lock_profile_obtain_lock_failed(&sx->lock_object, &contested, &waittime); #ifdef ADAPTIVE_SX /* * If the lock is write locked and the owner is * running on another CPU, spin until the owner stops * running or the state of the lock changes. */ x = sx->sx_lock; if ((sx->lock_object.lo_flags & SX_NOADAPTIVE) == 0) { if ((x & SX_LOCK_SHARED) == 0) { x = SX_OWNER(x); owner = (struct thread *)x; if (TD_IS_RUNNING(owner)) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, sx, owner); GIANT_SAVE(); while (SX_OWNER(sx->sx_lock) == x && TD_IS_RUNNING(owner)) { cpu_spinwait(); #ifdef KDTRACE_HOOKS spin_cnt++; #endif } continue; } } else if (SX_SHARERS(x) && spintries < asx_retries) { GIANT_SAVE(); spintries++; for (i = 0; i < asx_loops; i++) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR4(KTR_LOCK, "%s: shared spinning on %p with %u and %u", __func__, sx, spintries, i); x = sx->sx_lock; if ((x & SX_LOCK_SHARED) == 0 || SX_SHARERS(x) == 0) break; cpu_spinwait(); #ifdef KDTRACE_HOOKS spin_cnt++; #endif } if (i != asx_loops) continue; } } #endif sleepq_lock(&sx->lock_object); x = sx->sx_lock; /* * If the lock was released while spinning on the * sleep queue chain lock, try again. */ if (x == SX_LOCK_UNLOCKED) { sleepq_release(&sx->lock_object); continue; } #ifdef ADAPTIVE_SX /* * The current lock owner might have started executing * on another CPU (or the lock could have changed * owners) while we were waiting on the sleep queue * chain lock. If so, drop the sleep queue lock and try * again. */ if (!(x & SX_LOCK_SHARED) && (sx->lock_object.lo_flags & SX_NOADAPTIVE) == 0) { owner = (struct thread *)SX_OWNER(x); if (TD_IS_RUNNING(owner)) { sleepq_release(&sx->lock_object); continue; } } #endif /* * If an exclusive lock was released with both shared * and exclusive waiters and a shared waiter hasn't * woken up and acquired the lock yet, sx_lock will be * set to SX_LOCK_UNLOCKED | SX_LOCK_EXCLUSIVE_WAITERS. * If we see that value, try to acquire it once. Note * that we have to preserve SX_LOCK_EXCLUSIVE_WAITERS * as there are other exclusive waiters still. If we * fail, restart the loop. */ if (x == (SX_LOCK_UNLOCKED | SX_LOCK_EXCLUSIVE_WAITERS)) { if (atomic_cmpset_acq_ptr(&sx->sx_lock, SX_LOCK_UNLOCKED | SX_LOCK_EXCLUSIVE_WAITERS, tid | SX_LOCK_EXCLUSIVE_WAITERS)) { sleepq_release(&sx->lock_object); CTR2(KTR_LOCK, "%s: %p claimed by new writer", __func__, sx); break; } sleepq_release(&sx->lock_object); continue; } /* * Try to set the SX_LOCK_EXCLUSIVE_WAITERS. If we fail, * than loop back and retry. */ if (!(x & SX_LOCK_EXCLUSIVE_WAITERS)) { if (!atomic_cmpset_ptr(&sx->sx_lock, x, x | SX_LOCK_EXCLUSIVE_WAITERS)) { sleepq_release(&sx->lock_object); continue; } if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p set excl waiters flag", __func__, sx); } /* * Since we have been unable to acquire the exclusive * lock and the exclusive waiters flag is set, we have * to sleep. */ if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p blocking on sleep queue", __func__, sx); #ifdef KDTRACE_HOOKS sleep_time -= lockstat_nsecs(); #endif GIANT_SAVE(); sleepq_add(&sx->lock_object, NULL, sx->lock_object.lo_name, SLEEPQ_SX | ((opts & SX_INTERRUPTIBLE) ? SLEEPQ_INTERRUPTIBLE : 0), SQ_EXCLUSIVE_QUEUE); if (!(opts & SX_INTERRUPTIBLE)) sleepq_wait(&sx->lock_object, 0); else error = sleepq_wait_sig(&sx->lock_object, 0); #ifdef KDTRACE_HOOKS sleep_time += lockstat_nsecs(); sleep_cnt++; #endif if (error) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: interruptible sleep by %p suspended by signal", __func__, sx); break; } if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p resuming from sleep queue", __func__, sx); } GIANT_RESTORE(); if (!error) LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_SX_XLOCK_ACQUIRE, sx, contested, waittime, file, line); #ifdef KDTRACE_HOOKS if (sleep_time) LOCKSTAT_RECORD1(LS_SX_XLOCK_BLOCK, sx, sleep_time); if (spin_cnt > sleep_cnt) LOCKSTAT_RECORD1(LS_SX_XLOCK_SPIN, sx, (spin_cnt - sleep_cnt)); #endif return (error); } /* * This function represents the so-called 'hard case' for sx_xunlock * operation. All 'easy case' failures are redirected to this. Note * that ideally this would be a static function, but it needs to be * accessible from at least sx.h. */ void _sx_xunlock_hard(struct sx *sx, uintptr_t tid, const char *file, int line) { uintptr_t x; int queue, wakeup_swapper; + if (SCHEDULER_STOPPED()) + return; + MPASS(!(sx->sx_lock & SX_LOCK_SHARED)); /* If the lock is recursed, then unrecurse one level. */ if (sx_xlocked(sx) && sx_recursed(sx)) { if ((--sx->sx_recurse) == 0) atomic_clear_ptr(&sx->sx_lock, SX_LOCK_RECURSED); if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p unrecursing", __func__, sx); return; } MPASS(sx->sx_lock & (SX_LOCK_SHARED_WAITERS | SX_LOCK_EXCLUSIVE_WAITERS)); if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p contested", __func__, sx); sleepq_lock(&sx->lock_object); x = SX_LOCK_UNLOCKED; /* * The wake up algorithm here is quite simple and probably not * ideal. It gives precedence to shared waiters if they are * present. For this condition, we have to preserve the * state of the exclusive waiters flag. * If interruptible sleeps left the shared queue empty avoid a * starvation for the threads sleeping on the exclusive queue by giving * them precedence and cleaning up the shared waiters bit anyway. */ if ((sx->sx_lock & SX_LOCK_SHARED_WAITERS) != 0 && sleepq_sleepcnt(&sx->lock_object, SQ_SHARED_QUEUE) != 0) { queue = SQ_SHARED_QUEUE; x |= (sx->sx_lock & SX_LOCK_EXCLUSIVE_WAITERS); } else queue = SQ_EXCLUSIVE_QUEUE; /* Wake up all the waiters for the specific queue. */ if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR3(KTR_LOCK, "%s: %p waking up all threads on %s queue", __func__, sx, queue == SQ_SHARED_QUEUE ? "shared" : "exclusive"); atomic_store_rel_ptr(&sx->sx_lock, x); wakeup_swapper = sleepq_broadcast(&sx->lock_object, SLEEPQ_SX, 0, queue); sleepq_release(&sx->lock_object); if (wakeup_swapper) kick_proc0(); } /* * This function represents the so-called 'hard case' for sx_slock * operation. All 'easy case' failures are redirected to this. Note * that ideally this would be a static function, but it needs to be * accessible from at least sx.h. */ int _sx_slock_hard(struct sx *sx, int opts, const char *file, int line) { GIANT_DECLARE; #ifdef ADAPTIVE_SX volatile struct thread *owner; #endif #ifdef LOCK_PROFILING uint64_t waittime = 0; int contested = 0; #endif uintptr_t x; int error = 0; #ifdef KDTRACE_HOOKS uint64_t spin_cnt = 0; uint64_t sleep_cnt = 0; int64_t sleep_time = 0; #endif + if (SCHEDULER_STOPPED()) + return (0); + /* * As with rwlocks, we don't make any attempt to try to block * shared locks once there is an exclusive waiter. */ for (;;) { #ifdef KDTRACE_HOOKS spin_cnt++; #endif x = sx->sx_lock; /* * If no other thread has an exclusive lock then try to bump up * the count of sharers. Since we have to preserve the state * of SX_LOCK_EXCLUSIVE_WAITERS, if we fail to acquire the * shared lock loop back and retry. */ if (x & SX_LOCK_SHARED) { MPASS(!(x & SX_LOCK_SHARED_WAITERS)); if (atomic_cmpset_acq_ptr(&sx->sx_lock, x, x + SX_ONE_SHARER)) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR4(KTR_LOCK, "%s: %p succeed %p -> %p", __func__, sx, (void *)x, (void *)(x + SX_ONE_SHARER)); break; } continue; } lock_profile_obtain_lock_failed(&sx->lock_object, &contested, &waittime); #ifdef ADAPTIVE_SX /* * If the owner is running on another CPU, spin until * the owner stops running or the state of the lock * changes. */ if ((sx->lock_object.lo_flags & SX_NOADAPTIVE) == 0) { x = SX_OWNER(x); owner = (struct thread *)x; if (TD_IS_RUNNING(owner)) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR3(KTR_LOCK, "%s: spinning on %p held by %p", __func__, sx, owner); GIANT_SAVE(); while (SX_OWNER(sx->sx_lock) == x && TD_IS_RUNNING(owner)) { #ifdef KDTRACE_HOOKS spin_cnt++; #endif cpu_spinwait(); } continue; } } #endif /* * Some other thread already has an exclusive lock, so * start the process of blocking. */ sleepq_lock(&sx->lock_object); x = sx->sx_lock; /* * The lock could have been released while we spun. * In this case loop back and retry. */ if (x & SX_LOCK_SHARED) { sleepq_release(&sx->lock_object); continue; } #ifdef ADAPTIVE_SX /* * If the owner is running on another CPU, spin until * the owner stops running or the state of the lock * changes. */ if (!(x & SX_LOCK_SHARED) && (sx->lock_object.lo_flags & SX_NOADAPTIVE) == 0) { owner = (struct thread *)SX_OWNER(x); if (TD_IS_RUNNING(owner)) { sleepq_release(&sx->lock_object); continue; } } #endif /* * Try to set the SX_LOCK_SHARED_WAITERS flag. If we * fail to set it drop the sleep queue lock and loop * back. */ if (!(x & SX_LOCK_SHARED_WAITERS)) { if (!atomic_cmpset_ptr(&sx->sx_lock, x, x | SX_LOCK_SHARED_WAITERS)) { sleepq_release(&sx->lock_object); continue; } if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p set shared waiters flag", __func__, sx); } /* * Since we have been unable to acquire the shared lock, * we have to sleep. */ if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p blocking on sleep queue", __func__, sx); #ifdef KDTRACE_HOOKS sleep_time -= lockstat_nsecs(); #endif GIANT_SAVE(); sleepq_add(&sx->lock_object, NULL, sx->lock_object.lo_name, SLEEPQ_SX | ((opts & SX_INTERRUPTIBLE) ? SLEEPQ_INTERRUPTIBLE : 0), SQ_SHARED_QUEUE); if (!(opts & SX_INTERRUPTIBLE)) sleepq_wait(&sx->lock_object, 0); else error = sleepq_wait_sig(&sx->lock_object, 0); #ifdef KDTRACE_HOOKS sleep_time += lockstat_nsecs(); sleep_cnt++; #endif if (error) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: interruptible sleep by %p suspended by signal", __func__, sx); break; } if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p resuming from sleep queue", __func__, sx); } if (error == 0) LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_SX_SLOCK_ACQUIRE, sx, contested, waittime, file, line); #ifdef KDTRACE_HOOKS if (sleep_time) LOCKSTAT_RECORD1(LS_SX_XLOCK_BLOCK, sx, sleep_time); if (spin_cnt > sleep_cnt) LOCKSTAT_RECORD1(LS_SX_XLOCK_SPIN, sx, (spin_cnt - sleep_cnt)); #endif GIANT_RESTORE(); return (error); } /* * This function represents the so-called 'hard case' for sx_sunlock * operation. All 'easy case' failures are redirected to this. Note * that ideally this would be a static function, but it needs to be * accessible from at least sx.h. */ void _sx_sunlock_hard(struct sx *sx, const char *file, int line) { uintptr_t x; int wakeup_swapper; + + if (SCHEDULER_STOPPED()) + return; for (;;) { x = sx->sx_lock; /* * We should never have sharers while at least one thread * holds a shared lock. */ KASSERT(!(x & SX_LOCK_SHARED_WAITERS), ("%s: waiting sharers", __func__)); /* * See if there is more than one shared lock held. If * so, just drop one and return. */ if (SX_SHARERS(x) > 1) { if (atomic_cmpset_rel_ptr(&sx->sx_lock, x, x - SX_ONE_SHARER)) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR4(KTR_LOCK, "%s: %p succeeded %p -> %p", __func__, sx, (void *)x, (void *)(x - SX_ONE_SHARER)); break; } continue; } /* * If there aren't any waiters for an exclusive lock, * then try to drop it quickly. */ if (!(x & SX_LOCK_EXCLUSIVE_WAITERS)) { MPASS(x == SX_SHARERS_LOCK(1)); if (atomic_cmpset_rel_ptr(&sx->sx_lock, SX_SHARERS_LOCK(1), SX_LOCK_UNLOCKED)) { if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p last succeeded", __func__, sx); break; } continue; } /* * At this point, there should just be one sharer with * exclusive waiters. */ MPASS(x == (SX_SHARERS_LOCK(1) | SX_LOCK_EXCLUSIVE_WAITERS)); sleepq_lock(&sx->lock_object); /* * Wake up semantic here is quite simple: * Just wake up all the exclusive waiters. * Note that the state of the lock could have changed, * so if it fails loop back and retry. */ if (!atomic_cmpset_rel_ptr(&sx->sx_lock, SX_SHARERS_LOCK(1) | SX_LOCK_EXCLUSIVE_WAITERS, SX_LOCK_UNLOCKED)) { sleepq_release(&sx->lock_object); continue; } if (LOCK_LOG_TEST(&sx->lock_object, 0)) CTR2(KTR_LOCK, "%s: %p waking up all thread on" "exclusive queue", __func__, sx); wakeup_swapper = sleepq_broadcast(&sx->lock_object, SLEEPQ_SX, 0, SQ_EXCLUSIVE_QUEUE); sleepq_release(&sx->lock_object); if (wakeup_swapper) kick_proc0(); break; } } #ifdef INVARIANT_SUPPORT #ifndef INVARIANTS #undef _sx_assert #endif /* * In the non-WITNESS case, sx_assert() can only detect that at least * *some* thread owns an slock, but it cannot guarantee that *this* * thread owns an slock. */ void _sx_assert(const struct sx *sx, int what, const char *file, int line) { #ifndef WITNESS int slocked = 0; #endif if (panicstr != NULL) return; switch (what) { case SA_SLOCKED: case SA_SLOCKED | SA_NOTRECURSED: case SA_SLOCKED | SA_RECURSED: #ifndef WITNESS slocked = 1; /* FALLTHROUGH */ #endif case SA_LOCKED: case SA_LOCKED | SA_NOTRECURSED: case SA_LOCKED | SA_RECURSED: #ifdef WITNESS witness_assert(&sx->lock_object, what, file, line); #else /* * If some other thread has an exclusive lock or we * have one and are asserting a shared lock, fail. * Also, if no one has a lock at all, fail. */ if (sx->sx_lock == SX_LOCK_UNLOCKED || (!(sx->sx_lock & SX_LOCK_SHARED) && (slocked || sx_xholder(sx) != curthread))) panic("Lock %s not %slocked @ %s:%d\n", sx->lock_object.lo_name, slocked ? "share " : "", file, line); if (!(sx->sx_lock & SX_LOCK_SHARED)) { if (sx_recursed(sx)) { if (what & SA_NOTRECURSED) panic("Lock %s recursed @ %s:%d\n", sx->lock_object.lo_name, file, line); } else if (what & SA_RECURSED) panic("Lock %s not recursed @ %s:%d\n", sx->lock_object.lo_name, file, line); } #endif break; case SA_XLOCKED: case SA_XLOCKED | SA_NOTRECURSED: case SA_XLOCKED | SA_RECURSED: if (sx_xholder(sx) != curthread) panic("Lock %s not exclusively locked @ %s:%d\n", sx->lock_object.lo_name, file, line); if (sx_recursed(sx)) { if (what & SA_NOTRECURSED) panic("Lock %s recursed @ %s:%d\n", sx->lock_object.lo_name, file, line); } else if (what & SA_RECURSED) panic("Lock %s not recursed @ %s:%d\n", sx->lock_object.lo_name, file, line); break; case SA_UNLOCKED: #ifdef WITNESS witness_assert(&sx->lock_object, what, file, line); #else /* * If we hold an exclusve lock fail. We can't * reliably check to see if we hold a shared lock or * not. */ if (sx_xholder(sx) == curthread) panic("Lock %s exclusively locked @ %s:%d\n", sx->lock_object.lo_name, file, line); #endif break; default: panic("Unknown sx lock assertion: %d @ %s:%d", what, file, line); } } #endif /* INVARIANT_SUPPORT */ #ifdef DDB static void db_show_sx(const struct lock_object *lock) { struct thread *td; const struct sx *sx; sx = (const struct sx *)lock; db_printf(" state: "); if (sx->sx_lock == SX_LOCK_UNLOCKED) db_printf("UNLOCKED\n"); else if (sx->sx_lock == SX_LOCK_DESTROYED) { db_printf("DESTROYED\n"); return; } else if (sx->sx_lock & SX_LOCK_SHARED) db_printf("SLOCK: %ju\n", (uintmax_t)SX_SHARERS(sx->sx_lock)); else { td = sx_xholder(sx); db_printf("XLOCK: %p (tid %d, pid %d, \"%s\")\n", td, td->td_tid, td->td_proc->p_pid, td->td_name); if (sx_recursed(sx)) db_printf(" recursed: %d\n", sx->sx_recurse); } db_printf(" waiters: "); switch(sx->sx_lock & (SX_LOCK_SHARED_WAITERS | SX_LOCK_EXCLUSIVE_WAITERS)) { case SX_LOCK_SHARED_WAITERS: db_printf("shared\n"); break; case SX_LOCK_EXCLUSIVE_WAITERS: db_printf("exclusive\n"); break; case SX_LOCK_SHARED_WAITERS | SX_LOCK_EXCLUSIVE_WAITERS: db_printf("exclusive and shared\n"); break; default: db_printf("none\n"); } } /* * Check to see if a thread that is blocked on a sleep queue is actually * blocked on an sx lock. If so, output some details and return true. * If the lock has an exclusive owner, return that in *ownerp. */ int sx_chain(struct thread *td, struct thread **ownerp) { struct sx *sx; /* * Check to see if this thread is blocked on an sx lock. * First, we check the lock class. If that is ok, then we * compare the lock name against the wait message. */ sx = td->td_wchan; if (LOCK_CLASS(&sx->lock_object) != &lock_class_sx || sx->lock_object.lo_name != td->td_wmesg) return (0); /* We think we have an sx lock, so output some details. */ db_printf("blocked on sx \"%s\" ", td->td_wmesg); *ownerp = sx_xholder(sx); if (sx->sx_lock & SX_LOCK_SHARED) db_printf("SLOCK (count %ju)\n", (uintmax_t)SX_SHARERS(sx->sx_lock)); else db_printf("XLOCK\n"); return (1); } #endif Index: head/sys/kern/kern_synch.c =================================================================== --- head/sys/kern/kern_synch.c (revision 228423) +++ head/sys/kern/kern_synch.c (revision 228424) @@ -1,604 +1,606 @@ /*- * Copyright (c) 1982, 1986, 1990, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)kern_synch.c 8.9 (Berkeley) 5/19/95 */ #include __FBSDID("$FreeBSD$"); #include "opt_ktrace.h" #include "opt_sched.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef KTRACE #include #include #endif #include #ifdef XEN #include #include #include #endif #define KTDSTATE(td) \ (((td)->td_inhibitors & TDI_SLEEPING) != 0 ? "sleep" : \ ((td)->td_inhibitors & TDI_SUSPENDED) != 0 ? "suspended" : \ ((td)->td_inhibitors & TDI_SWAPPED) != 0 ? "swapped" : \ ((td)->td_inhibitors & TDI_LOCK) != 0 ? "blocked" : \ ((td)->td_inhibitors & TDI_IWAIT) != 0 ? "iwait" : "yielding") static void synch_setup(void *dummy); SYSINIT(synch_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, synch_setup, NULL); int hogticks; static int pause_wchan; static struct callout loadav_callout; struct loadavg averunnable = { {0, 0, 0}, FSCALE }; /* load average, of runnable procs */ /* * Constants for averages over 1, 5, and 15 minutes * when sampling at 5 second intervals. */ static fixpt_t cexp[3] = { 0.9200444146293232 * FSCALE, /* exp(-1/12) */ 0.9834714538216174 * FSCALE, /* exp(-1/60) */ 0.9944598480048967 * FSCALE, /* exp(-1/180) */ }; /* kernel uses `FSCALE', userland (SHOULD) use kern.fscale */ static int fscale __unused = FSCALE; SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, ""); static void loadav(void *arg); void sleepinit(void) { hogticks = (hz / 10) * 2; /* Default only. */ init_sleepqueues(); } /* * General sleep call. Suspends the current thread until a wakeup is * performed on the specified identifier. The thread will then be made * runnable with the specified priority. Sleeps at most timo/hz seconds * (0 means no timeout). If pri includes PCATCH flag, signals are checked * before and after sleeping, else signals are not checked. Returns 0 if * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a * signal needs to be delivered, ERESTART is returned if the current system * call should be restarted if possible, and EINTR is returned if the system * call should be interrupted by the signal (return EINTR). * * The lock argument is unlocked before the caller is suspended, and * re-locked before _sleep() returns. If priority includes the PDROP * flag the lock is not re-locked before returning. */ int _sleep(void *ident, struct lock_object *lock, int priority, const char *wmesg, int timo) { struct thread *td; struct proc *p; struct lock_class *class; int catch, flags, lock_state, pri, rval; WITNESS_SAVE_DECL(lock_witness); td = curthread; p = td->td_proc; #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) ktrcsw(1, 0); #endif WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, lock, "Sleeping on \"%s\"", wmesg); KASSERT(timo != 0 || mtx_owned(&Giant) || lock != NULL, ("sleeping without a lock")); KASSERT(p != NULL, ("msleep1")); KASSERT(ident != NULL && TD_IS_RUNNING(td), ("msleep")); if (priority & PDROP) KASSERT(lock != NULL && lock != &Giant.lock_object, ("PDROP requires a non-Giant lock")); if (lock != NULL) class = LOCK_CLASS(lock); else class = NULL; - if (cold) { + if (cold || SCHEDULER_STOPPED()) { /* * During autoconfiguration, just return; * don't run any other threads or panic below, * in case this is the idle thread and already asleep. * XXX: this used to do "s = splhigh(); splx(safepri); * splx(s);" to give interrupts a chance, but there is * no way to give interrupts a chance now. */ if (lock != NULL && priority & PDROP) class->lc_unlock(lock); return (0); } catch = priority & PCATCH; pri = priority & PRIMASK; /* * If we are already on a sleep queue, then remove us from that * sleep queue first. We have to do this to handle recursive * sleeps. */ if (TD_ON_SLEEPQ(td)) sleepq_remove(td, td->td_wchan); if (ident == &pause_wchan) flags = SLEEPQ_PAUSE; else flags = SLEEPQ_SLEEP; if (catch) flags |= SLEEPQ_INTERRUPTIBLE; if (priority & PBDRY) flags |= SLEEPQ_STOP_ON_BDRY; sleepq_lock(ident); CTR5(KTR_PROC, "sleep: thread %ld (pid %ld, %s) on %s (%p)", td->td_tid, p->p_pid, td->td_name, wmesg, ident); if (lock == &Giant.lock_object) mtx_assert(&Giant, MA_OWNED); DROP_GIANT(); if (lock != NULL && lock != &Giant.lock_object && !(class->lc_flags & LC_SLEEPABLE)) { WITNESS_SAVE(lock, lock_witness); lock_state = class->lc_unlock(lock); } else /* GCC needs to follow the Yellow Brick Road */ lock_state = -1; /* * We put ourselves on the sleep queue and start our timeout * before calling thread_suspend_check, as we could stop there, * and a wakeup or a SIGCONT (or both) could occur while we were * stopped without resuming us. Thus, we must be ready for sleep * when cursig() is called. If the wakeup happens while we're * stopped, then td will no longer be on a sleep queue upon * return from cursig(). */ sleepq_add(ident, lock, wmesg, flags, 0); if (timo) sleepq_set_timeout(ident, timo); if (lock != NULL && class->lc_flags & LC_SLEEPABLE) { sleepq_release(ident); WITNESS_SAVE(lock, lock_witness); lock_state = class->lc_unlock(lock); sleepq_lock(ident); } if (timo && catch) rval = sleepq_timedwait_sig(ident, pri); else if (timo) rval = sleepq_timedwait(ident, pri); else if (catch) rval = sleepq_wait_sig(ident, pri); else { sleepq_wait(ident, pri); rval = 0; } #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) ktrcsw(0, 0); #endif PICKUP_GIANT(); if (lock != NULL && lock != &Giant.lock_object && !(priority & PDROP)) { class->lc_lock(lock, lock_state); WITNESS_RESTORE(lock, lock_witness); } return (rval); } int msleep_spin(void *ident, struct mtx *mtx, const char *wmesg, int timo) { struct thread *td; struct proc *p; int rval; WITNESS_SAVE_DECL(mtx); td = curthread; p = td->td_proc; KASSERT(mtx != NULL, ("sleeping without a mutex")); KASSERT(p != NULL, ("msleep1")); KASSERT(ident != NULL && TD_IS_RUNNING(td), ("msleep")); - if (cold) { + if (cold || SCHEDULER_STOPPED()) { /* * During autoconfiguration, just return; * don't run any other threads or panic below, * in case this is the idle thread and already asleep. * XXX: this used to do "s = splhigh(); splx(safepri); * splx(s);" to give interrupts a chance, but there is * no way to give interrupts a chance now. */ return (0); } sleepq_lock(ident); CTR5(KTR_PROC, "msleep_spin: thread %ld (pid %ld, %s) on %s (%p)", td->td_tid, p->p_pid, td->td_name, wmesg, ident); DROP_GIANT(); mtx_assert(mtx, MA_OWNED | MA_NOTRECURSED); WITNESS_SAVE(&mtx->lock_object, mtx); mtx_unlock_spin(mtx); /* * We put ourselves on the sleep queue and start our timeout. */ sleepq_add(ident, &mtx->lock_object, wmesg, SLEEPQ_SLEEP, 0); if (timo) sleepq_set_timeout(ident, timo); /* * Can't call ktrace with any spin locks held so it can lock the * ktrace_mtx lock, and WITNESS_WARN considers it an error to hold * any spin lock. Thus, we have to drop the sleepq spin lock while * we handle those requests. This is safe since we have placed our * thread on the sleep queue already. */ #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) { sleepq_release(ident); ktrcsw(1, 0); sleepq_lock(ident); } #endif #ifdef WITNESS sleepq_release(ident); WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "Sleeping on \"%s\"", wmesg); sleepq_lock(ident); #endif if (timo) rval = sleepq_timedwait(ident, 0); else { sleepq_wait(ident, 0); rval = 0; } #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) ktrcsw(0, 0); #endif PICKUP_GIANT(); mtx_lock_spin(mtx); WITNESS_RESTORE(&mtx->lock_object, mtx); return (rval); } /* * pause() delays the calling thread by the given number of system ticks. * During cold bootup, pause() uses the DELAY() function instead of * the tsleep() function to do the waiting. The "timo" argument must be * greater than or equal to zero. A "timo" value of zero is equivalent * to a "timo" value of one. */ int pause(const char *wmesg, int timo) { KASSERT(timo >= 0, ("pause: timo must be >= 0")); /* silently convert invalid timeouts */ if (timo < 1) timo = 1; if (cold) { /* * We delay one HZ at a time to avoid overflowing the * system specific DELAY() function(s): */ while (timo >= hz) { DELAY(1000000); timo -= hz; } if (timo > 0) DELAY(timo * tick); return (0); } return (tsleep(&pause_wchan, 0, wmesg, timo)); } /* * Make all threads sleeping on the specified identifier runnable. */ void wakeup(void *ident) { int wakeup_swapper; sleepq_lock(ident); wakeup_swapper = sleepq_broadcast(ident, SLEEPQ_SLEEP, 0, 0); sleepq_release(ident); if (wakeup_swapper) { KASSERT(ident != &proc0, ("wakeup and wakeup_swapper and proc0")); kick_proc0(); } } /* * Make a thread sleeping on the specified identifier runnable. * May wake more than one thread if a target thread is currently * swapped out. */ void wakeup_one(void *ident) { int wakeup_swapper; sleepq_lock(ident); wakeup_swapper = sleepq_signal(ident, SLEEPQ_SLEEP, 0, 0); sleepq_release(ident); if (wakeup_swapper) kick_proc0(); } static void kdb_switch(void) { thread_unlock(curthread); kdb_backtrace(); kdb_reenter(); panic("%s: did not reenter debugger", __func__); } /* * The machine independent parts of context switching. */ void mi_switch(int flags, struct thread *newtd) { uint64_t runtime, new_switchtime; struct thread *td; struct proc *p; td = curthread; /* XXX */ THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED); p = td->td_proc; /* XXX */ KASSERT(!TD_ON_RUNQ(td), ("mi_switch: called by old code")); #ifdef INVARIANTS if (!TD_ON_LOCK(td) && !TD_IS_RUNNING(td)) mtx_assert(&Giant, MA_NOTOWNED); #endif KASSERT(td->td_critnest == 1 || panicstr, ("mi_switch: switch in a critical section")); KASSERT((flags & (SW_INVOL | SW_VOL)) != 0, ("mi_switch: switch must be voluntary or involuntary")); KASSERT(newtd != curthread, ("mi_switch: preempting back to ourself")); /* * Don't perform context switches from the debugger. */ if (kdb_active) kdb_switch(); + if (SCHEDULER_STOPPED()) + return; if (flags & SW_VOL) { td->td_ru.ru_nvcsw++; td->td_swvoltick = ticks; } else td->td_ru.ru_nivcsw++; #ifdef SCHED_STATS SCHED_STAT_INC(sched_switch_stats[flags & SW_TYPE_MASK]); #endif /* * Compute the amount of time during which the current * thread was running, and add that to its total so far. */ new_switchtime = cpu_ticks(); runtime = new_switchtime - PCPU_GET(switchtime); td->td_runtime += runtime; td->td_incruntime += runtime; PCPU_SET(switchtime, new_switchtime); td->td_generation++; /* bump preempt-detect counter */ PCPU_INC(cnt.v_swtch); PCPU_SET(switchticks, ticks); CTR4(KTR_PROC, "mi_switch: old thread %ld (td_sched %p, pid %ld, %s)", td->td_tid, td->td_sched, p->p_pid, td->td_name); #if (KTR_COMPILE & KTR_SCHED) != 0 if (TD_IS_IDLETHREAD(td)) KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "idle", "prio:%d", td->td_priority); else KTR_STATE3(KTR_SCHED, "thread", sched_tdname(td), KTDSTATE(td), "prio:%d", td->td_priority, "wmesg:\"%s\"", td->td_wmesg, "lockname:\"%s\"", td->td_lockname); #endif #ifdef XEN PT_UPDATES_FLUSH(); #endif sched_switch(td, newtd, flags); KTR_STATE1(KTR_SCHED, "thread", sched_tdname(td), "running", "prio:%d", td->td_priority); CTR4(KTR_PROC, "mi_switch: new thread %ld (td_sched %p, pid %ld, %s)", td->td_tid, td->td_sched, p->p_pid, td->td_name); /* * If the last thread was exiting, finish cleaning it up. */ if ((td = PCPU_GET(deadthread))) { PCPU_SET(deadthread, NULL); thread_stash(td); } } /* * Change thread state to be runnable, placing it on the run queue if * it is in memory. If it is swapped out, return true so our caller * will know to awaken the swapper. */ int setrunnable(struct thread *td) { THREAD_LOCK_ASSERT(td, MA_OWNED); KASSERT(td->td_proc->p_state != PRS_ZOMBIE, ("setrunnable: pid %d is a zombie", td->td_proc->p_pid)); switch (td->td_state) { case TDS_RUNNING: case TDS_RUNQ: return (0); case TDS_INHIBITED: /* * If we are only inhibited because we are swapped out * then arange to swap in this process. Otherwise just return. */ if (td->td_inhibitors != TDI_SWAPPED) return (0); /* FALLTHROUGH */ case TDS_CAN_RUN: break; default: printf("state is 0x%x", td->td_state); panic("setrunnable(2)"); } if ((td->td_flags & TDF_INMEM) == 0) { if ((td->td_flags & TDF_SWAPINREQ) == 0) { td->td_flags |= TDF_SWAPINREQ; return (1); } } else sched_wakeup(td); return (0); } /* * Compute a tenex style load average of a quantity on * 1, 5 and 15 minute intervals. */ static void loadav(void *arg) { int i, nrun; struct loadavg *avg; nrun = sched_load(); avg = &averunnable; for (i = 0; i < 3; i++) avg->ldavg[i] = (cexp[i] * avg->ldavg[i] + nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT; /* * Schedule the next update to occur after 5 seconds, but add a * random variation to avoid synchronisation with processes that * run at regular intervals. */ callout_reset(&loadav_callout, hz * 4 + (int)(random() % (hz * 2 + 1)), loadav, NULL); } /* ARGSUSED */ static void synch_setup(void *dummy) { callout_init(&loadav_callout, CALLOUT_MPSAFE); /* Kick off timeout driven events by calling first time. */ loadav(NULL); } int should_yield(void) { return (ticks - curthread->td_swvoltick >= hogticks); } void maybe_yield(void) { if (should_yield()) kern_yield(PRI_USER); } void kern_yield(int prio) { struct thread *td; td = curthread; DROP_GIANT(); thread_lock(td); if (prio == PRI_USER) prio = td->td_user_pri; if (prio >= 0) sched_prio(td, prio); mi_switch(SW_VOL | SWT_RELINQUISH, NULL); thread_unlock(td); PICKUP_GIANT(); } /* * General purpose yield system call. */ int sys_yield(struct thread *td, struct yield_args *uap) { thread_lock(td); if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) sched_prio(td, PRI_MAX_TIMESHARE); mi_switch(SW_VOL | SWT_RELINQUISH, NULL); thread_unlock(td); td->td_retval[0] = 0; return (0); } Index: head/sys/kern/subr_kdb.c =================================================================== --- head/sys/kern/subr_kdb.c (revision 228423) +++ head/sys/kern/subr_kdb.c (revision 228424) @@ -1,643 +1,645 @@ /*- * Copyright (c) 2004 The FreeBSD Project * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include "opt_kdb.h" #include "opt_stack.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef SMP #include #endif int kdb_active = 0; static void *kdb_jmpbufp = NULL; struct kdb_dbbe *kdb_dbbe = NULL; static struct pcb kdb_pcb; struct pcb *kdb_thrctx = NULL; struct thread *kdb_thread = NULL; struct trapframe *kdb_frame = NULL; #ifdef BREAK_TO_DEBUGGER #define KDB_BREAK_TO_DEBUGGER 1 #else #define KDB_BREAK_TO_DEBUGGER 0 #endif #ifdef ALT_BREAK_TO_DEBUGGER #define KDB_ALT_BREAK_TO_DEBUGGER 1 #else #define KDB_ALT_BREAK_TO_DEBUGGER 0 #endif static int kdb_break_to_debugger = KDB_BREAK_TO_DEBUGGER; static int kdb_alt_break_to_debugger = KDB_ALT_BREAK_TO_DEBUGGER; KDB_BACKEND(null, NULL, NULL, NULL); SET_DECLARE(kdb_dbbe_set, struct kdb_dbbe); static int kdb_sysctl_available(SYSCTL_HANDLER_ARGS); static int kdb_sysctl_current(SYSCTL_HANDLER_ARGS); static int kdb_sysctl_enter(SYSCTL_HANDLER_ARGS); static int kdb_sysctl_panic(SYSCTL_HANDLER_ARGS); static int kdb_sysctl_trap(SYSCTL_HANDLER_ARGS); static int kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS); static SYSCTL_NODE(_debug, OID_AUTO, kdb, CTLFLAG_RW, NULL, "KDB nodes"); SYSCTL_PROC(_debug_kdb, OID_AUTO, available, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, kdb_sysctl_available, "A", "list of available KDB backends"); SYSCTL_PROC(_debug_kdb, OID_AUTO, current, CTLTYPE_STRING | CTLFLAG_RW, NULL, 0, kdb_sysctl_current, "A", "currently selected KDB backend"); SYSCTL_PROC(_debug_kdb, OID_AUTO, enter, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, NULL, 0, kdb_sysctl_enter, "I", "set to enter the debugger"); SYSCTL_PROC(_debug_kdb, OID_AUTO, panic, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, NULL, 0, kdb_sysctl_panic, "I", "set to panic the kernel"); SYSCTL_PROC(_debug_kdb, OID_AUTO, trap, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, NULL, 0, kdb_sysctl_trap, "I", "set to cause a page fault via data access"); SYSCTL_PROC(_debug_kdb, OID_AUTO, trap_code, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, NULL, 0, kdb_sysctl_trap_code, "I", "set to cause a page fault via code access"); SYSCTL_INT(_debug_kdb, OID_AUTO, break_to_debugger, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_TUN | CTLFLAG_SECURE, &kdb_break_to_debugger, 0, "Enable break to debugger"); TUNABLE_INT("debug.kdb.break_to_debugger", &kdb_break_to_debugger); SYSCTL_INT(_debug_kdb, OID_AUTO, alt_break_to_debugger, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_TUN | CTLFLAG_SECURE, &kdb_alt_break_to_debugger, 0, "Enable alternative break to debugger"); TUNABLE_INT("debug.kdb.alt_break_to_debugger", &kdb_alt_break_to_debugger); /* * Flag to indicate to debuggers why the debugger was entered. */ const char * volatile kdb_why = KDB_WHY_UNSET; static int kdb_sysctl_available(SYSCTL_HANDLER_ARGS) { struct kdb_dbbe **iter; struct sbuf sbuf; int error; sbuf_new_for_sysctl(&sbuf, NULL, 64, req); SET_FOREACH(iter, kdb_dbbe_set) { if ((*iter)->dbbe_active == 0) sbuf_printf(&sbuf, "%s ", (*iter)->dbbe_name); } error = sbuf_finish(&sbuf); sbuf_delete(&sbuf); return (error); } static int kdb_sysctl_current(SYSCTL_HANDLER_ARGS) { char buf[16]; int error; if (kdb_dbbe != NULL) strlcpy(buf, kdb_dbbe->dbbe_name, sizeof(buf)); else *buf = '\0'; error = sysctl_handle_string(oidp, buf, sizeof(buf), req); if (error != 0 || req->newptr == NULL) return (error); if (kdb_active) return (EBUSY); return (kdb_dbbe_select(buf)); } static int kdb_sysctl_enter(SYSCTL_HANDLER_ARGS) { int error, i; error = sysctl_wire_old_buffer(req, sizeof(int)); if (error == 0) { i = 0; error = sysctl_handle_int(oidp, &i, 0, req); } if (error != 0 || req->newptr == NULL) return (error); if (kdb_active) return (EBUSY); kdb_enter(KDB_WHY_SYSCTL, "sysctl debug.kdb.enter"); return (0); } static int kdb_sysctl_panic(SYSCTL_HANDLER_ARGS) { int error, i; error = sysctl_wire_old_buffer(req, sizeof(int)); if (error == 0) { i = 0; error = sysctl_handle_int(oidp, &i, 0, req); } if (error != 0 || req->newptr == NULL) return (error); panic("kdb_sysctl_panic"); return (0); } static int kdb_sysctl_trap(SYSCTL_HANDLER_ARGS) { int error, i; int *addr = (int *)0x10; error = sysctl_wire_old_buffer(req, sizeof(int)); if (error == 0) { i = 0; error = sysctl_handle_int(oidp, &i, 0, req); } if (error != 0 || req->newptr == NULL) return (error); return (*addr); } static int kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS) { int error, i; void (*fp)(u_int, u_int, u_int) = (void *)0xdeadc0de; error = sysctl_wire_old_buffer(req, sizeof(int)); if (error == 0) { i = 0; error = sysctl_handle_int(oidp, &i, 0, req); } if (error != 0 || req->newptr == NULL) return (error); (*fp)(0x11111111, 0x22222222, 0x33333333); return (0); } void kdb_panic(const char *msg) { -#ifdef SMP - cpuset_t other_cpus; - other_cpus = all_cpus; - CPU_CLR(PCPU_GET(cpuid), &other_cpus); - stop_cpus_hard(other_cpus); -#endif printf("KDB: panic\n"); panic("%s", msg); } void kdb_reboot(void) { printf("KDB: reboot requested\n"); shutdown_nice(0); } /* * Solaris implements a new BREAK which is initiated by a character sequence * CR ~ ^b which is similar to a familiar pattern used on Sun servers by the * Remote Console. * * Note that this function may be called from almost anywhere, with interrupts * disabled and with unknown locks held, so it must not access data other than * its arguments. Its up to the caller to ensure that the state variable is * consistent. */ #define KEY_CR 13 /* CR '\r' */ #define KEY_TILDE 126 /* ~ */ #define KEY_CRTLB 2 /* ^B */ #define KEY_CRTLP 16 /* ^P */ #define KEY_CRTLR 18 /* ^R */ /* States of th KDB "alternate break sequence" detecting state machine. */ enum { KDB_ALT_BREAK_SEEN_NONE, KDB_ALT_BREAK_SEEN_CR, KDB_ALT_BREAK_SEEN_CR_TILDE, }; int kdb_break(void) { if (!kdb_break_to_debugger) return (0); kdb_enter(KDB_WHY_BREAK, "Break to debugger"); return (KDB_REQ_DEBUGGER); } static int kdb_alt_break_state(int key, int *state) { int brk; /* All states transition to KDB_ALT_BREAK_SEEN_CR on a CR. */ if (key == KEY_CR) { *state = KDB_ALT_BREAK_SEEN_CR; return (0); } brk = 0; switch (*state) { case KDB_ALT_BREAK_SEEN_CR: *state = KDB_ALT_BREAK_SEEN_NONE; if (key == KEY_TILDE) *state = KDB_ALT_BREAK_SEEN_CR_TILDE; break; case KDB_ALT_BREAK_SEEN_CR_TILDE: *state = KDB_ALT_BREAK_SEEN_NONE; if (key == KEY_CRTLB) brk = KDB_REQ_DEBUGGER; else if (key == KEY_CRTLP) brk = KDB_REQ_PANIC; else if (key == KEY_CRTLR) brk = KDB_REQ_REBOOT; break; case KDB_ALT_BREAK_SEEN_NONE: default: *state = KDB_ALT_BREAK_SEEN_NONE; break; } return (brk); } static int kdb_alt_break_internal(int key, int *state, int force_gdb) { int brk; if (!kdb_alt_break_to_debugger) return (0); brk = kdb_alt_break_state(key, state); switch (brk) { case KDB_REQ_DEBUGGER: if (force_gdb) kdb_dbbe_select("gdb"); kdb_enter(KDB_WHY_BREAK, "Break to debugger"); break; case KDB_REQ_PANIC: if (force_gdb) kdb_dbbe_select("gdb"); kdb_panic("Panic sequence on console"); break; case KDB_REQ_REBOOT: kdb_reboot(); break; } return (0); } int kdb_alt_break(int key, int *state) { return (kdb_alt_break_internal(key, state, 0)); } /* * This variation on kdb_alt_break() is used only by dcons, which has its own * configuration flag to force GDB use regardless of the global KDB * configuration. */ int kdb_alt_break_gdb(int key, int *state) { return (kdb_alt_break_internal(key, state, 1)); } /* * Print a backtrace of the calling thread. The backtrace is generated by * the selected debugger, provided it supports backtraces. If no debugger * is selected or the current debugger does not support backtraces, this * function silently returns. */ void kdb_backtrace(void) { if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace != NULL) { printf("KDB: stack backtrace:\n"); kdb_dbbe->dbbe_trace(); } #ifdef STACK else { struct stack st; printf("KDB: stack backtrace:\n"); stack_save(&st); stack_print_ddb(&st); } #endif } /* * Set/change the current backend. */ int kdb_dbbe_select(const char *name) { struct kdb_dbbe *be, **iter; SET_FOREACH(iter, kdb_dbbe_set) { be = *iter; if (be->dbbe_active == 0 && strcmp(be->dbbe_name, name) == 0) { kdb_dbbe = be; return (0); } } return (EINVAL); } /* * Enter the currently selected debugger. If a message has been provided, * it is printed first. If the debugger does not support the enter method, * it is entered by using breakpoint(), which enters the debugger through * kdb_trap(). The 'why' argument will contain a more mechanically usable * string than 'msg', and is relied upon by DDB scripting to identify the * reason for entering the debugger so that the right script can be run. */ void kdb_enter(const char *why, const char *msg) { if (kdb_dbbe != NULL && kdb_active == 0) { if (msg != NULL) printf("KDB: enter: %s\n", msg); kdb_why = why; breakpoint(); kdb_why = KDB_WHY_UNSET; } } /* * Initialize the kernel debugger interface. */ void kdb_init(void) { struct kdb_dbbe *be, **iter; int cur_pri, pri; kdb_active = 0; kdb_dbbe = NULL; cur_pri = -1; SET_FOREACH(iter, kdb_dbbe_set) { be = *iter; pri = (be->dbbe_init != NULL) ? be->dbbe_init() : -1; be->dbbe_active = (pri >= 0) ? 0 : -1; if (pri > cur_pri) { cur_pri = pri; kdb_dbbe = be; } } if (kdb_dbbe != NULL) { printf("KDB: debugger backends:"); SET_FOREACH(iter, kdb_dbbe_set) { be = *iter; if (be->dbbe_active == 0) printf(" %s", be->dbbe_name); } printf("\n"); printf("KDB: current backend: %s\n", kdb_dbbe->dbbe_name); } } /* * Handle contexts. */ void * kdb_jmpbuf(jmp_buf new) { void *old; old = kdb_jmpbufp; kdb_jmpbufp = new; return (old); } void kdb_reenter(void) { if (!kdb_active || kdb_jmpbufp == NULL) return; longjmp(kdb_jmpbufp, 1); /* NOTREACHED */ } /* * Thread related support functions. */ struct pcb * kdb_thr_ctx(struct thread *thr) { #if defined(SMP) && defined(KDB_STOPPEDPCB) struct pcpu *pc; #endif if (thr == curthread) return (&kdb_pcb); #if defined(SMP) && defined(KDB_STOPPEDPCB) STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) { if (pc->pc_curthread == thr && CPU_ISSET(pc->pc_cpuid, &stopped_cpus)) return (KDB_STOPPEDPCB(pc)); } #endif return (thr->td_pcb); } struct thread * kdb_thr_first(void) { struct proc *p; struct thread *thr; p = LIST_FIRST(&allproc); while (p != NULL) { if (p->p_flag & P_INMEM) { thr = FIRST_THREAD_IN_PROC(p); if (thr != NULL) return (thr); } p = LIST_NEXT(p, p_list); } return (NULL); } struct thread * kdb_thr_from_pid(pid_t pid) { struct proc *p; p = LIST_FIRST(&allproc); while (p != NULL) { if (p->p_flag & P_INMEM && p->p_pid == pid) return (FIRST_THREAD_IN_PROC(p)); p = LIST_NEXT(p, p_list); } return (NULL); } struct thread * kdb_thr_lookup(lwpid_t tid) { struct thread *thr; thr = kdb_thr_first(); while (thr != NULL && thr->td_tid != tid) thr = kdb_thr_next(thr); return (thr); } struct thread * kdb_thr_next(struct thread *thr) { struct proc *p; p = thr->td_proc; thr = TAILQ_NEXT(thr, td_plist); do { if (thr != NULL) return (thr); p = LIST_NEXT(p, p_list); if (p != NULL && (p->p_flag & P_INMEM)) thr = FIRST_THREAD_IN_PROC(p); } while (p != NULL); return (NULL); } int kdb_thr_select(struct thread *thr) { if (thr == NULL) return (EINVAL); kdb_thread = thr; kdb_thrctx = kdb_thr_ctx(thr); return (0); } /* * Enter the debugger due to a trap. */ int kdb_trap(int type, int code, struct trapframe *tf) { #ifdef SMP cpuset_t other_cpus; #endif struct kdb_dbbe *be; register_t intr; int handled; +#ifdef SMP + int did_stop_cpus; +#endif be = kdb_dbbe; if (be == NULL || be->dbbe_trap == NULL) return (0); /* We reenter the debugger through kdb_reenter(). */ if (kdb_active) return (0); intr = intr_disable(); #ifdef SMP - other_cpus = all_cpus; - CPU_CLR(PCPU_GET(cpuid), &other_cpus); - stop_cpus_hard(other_cpus); + if (!SCHEDULER_STOPPED()) { + other_cpus = all_cpus; + CPU_CLR(PCPU_GET(cpuid), &other_cpus); + stop_cpus_hard(other_cpus); + did_stop_cpus = 1; + } else + did_stop_cpus = 0; #endif kdb_active++; kdb_frame = tf; /* Let MD code do its thing first... */ kdb_cpu_trap(type, code); makectx(tf, &kdb_pcb); kdb_thr_select(curthread); for (;;) { handled = be->dbbe_trap(type, code); if (be == kdb_dbbe) break; be = kdb_dbbe; if (be == NULL || be->dbbe_trap == NULL) break; printf("Switching to %s back-end\n", be->dbbe_name); } kdb_active--; #ifdef SMP - restart_cpus(stopped_cpus); + if (did_stop_cpus) + restart_cpus(stopped_cpus); #endif intr_restore(intr); return (handled); } Index: head/sys/kern/subr_lock.c =================================================================== --- head/sys/kern/subr_lock.c (revision 228423) +++ head/sys/kern/subr_lock.c (revision 228424) @@ -1,664 +1,669 @@ /*- * Copyright (c) 2006 John Baldwin * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the author nor the names of any co-contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * This module holds the global variables and functions used to maintain * lock_object structures. */ #include __FBSDID("$FreeBSD$"); #include "opt_ddb.h" #include "opt_mprof.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DDB #include #endif #include CTASSERT(LOCK_CLASS_MAX == 15); struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = { &lock_class_mtx_spin, &lock_class_mtx_sleep, &lock_class_sx, &lock_class_rm, &lock_class_rw, &lock_class_lockmgr, }; void lock_init(struct lock_object *lock, struct lock_class *class, const char *name, const char *type, int flags) { int i; /* Check for double-init and zero object. */ KASSERT(!lock_initalized(lock), ("lock \"%s\" %p already initialized", name, lock)); /* Look up lock class to find its index. */ for (i = 0; i < LOCK_CLASS_MAX; i++) if (lock_classes[i] == class) { lock->lo_flags = i << LO_CLASSSHIFT; break; } KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class)); /* Initialize the lock object. */ lock->lo_name = name; lock->lo_flags |= flags | LO_INITIALIZED; LOCK_LOG_INIT(lock, 0); WITNESS_INIT(lock, (type != NULL) ? type : name); } void lock_destroy(struct lock_object *lock) { KASSERT(lock_initalized(lock), ("lock %p is not initialized", lock)); WITNESS_DESTROY(lock); LOCK_LOG_DESTROY(lock, 0); lock->lo_flags &= ~LO_INITIALIZED; } #ifdef DDB DB_SHOW_COMMAND(lock, db_show_lock) { struct lock_object *lock; struct lock_class *class; if (!have_addr) return; lock = (struct lock_object *)addr; if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) { db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock)); return; } class = LOCK_CLASS(lock); db_printf(" class: %s\n", class->lc_name); db_printf(" name: %s\n", lock->lo_name); class->lc_ddb_show(lock); } #endif #ifdef LOCK_PROFILING /* * One object per-thread for each lock the thread owns. Tracks individual * lock instances. */ struct lock_profile_object { LIST_ENTRY(lock_profile_object) lpo_link; struct lock_object *lpo_obj; const char *lpo_file; int lpo_line; uint16_t lpo_ref; uint16_t lpo_cnt; uint64_t lpo_acqtime; uint64_t lpo_waittime; u_int lpo_contest_locking; }; /* * One lock_prof for each (file, line, lock object) triple. */ struct lock_prof { SLIST_ENTRY(lock_prof) link; struct lock_class *class; const char *file; const char *name; int line; int ticks; uintmax_t cnt_wait_max; uintmax_t cnt_max; uintmax_t cnt_tot; uintmax_t cnt_wait; uintmax_t cnt_cur; uintmax_t cnt_contest_locking; }; SLIST_HEAD(lphead, lock_prof); #define LPROF_HASH_SIZE 4096 #define LPROF_HASH_MASK (LPROF_HASH_SIZE - 1) #define LPROF_CACHE_SIZE 4096 /* * Array of objects and profs for each type of object for each cpu. Spinlocks * are handled separately because a thread may be preempted and acquire a * spinlock while in the lock profiling code of a non-spinlock. In this way * we only need a critical section to protect the per-cpu lists. */ struct lock_prof_type { struct lphead lpt_lpalloc; struct lpohead lpt_lpoalloc; struct lphead lpt_hash[LPROF_HASH_SIZE]; struct lock_prof lpt_prof[LPROF_CACHE_SIZE]; struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE]; }; struct lock_prof_cpu { struct lock_prof_type lpc_types[2]; /* One for spin one for other. */ }; struct lock_prof_cpu *lp_cpu[MAXCPU]; volatile int lock_prof_enable = 0; static volatile int lock_prof_resetting; #define LPROF_SBUF_SIZE 256 static int lock_prof_rejected; static int lock_prof_skipspin; static int lock_prof_skipcount; #ifndef USE_CPU_NANOSECONDS uint64_t nanoseconds(void) { struct bintime bt; uint64_t ns; binuptime(&bt); /* From bintime2timespec */ ns = bt.sec * (uint64_t)1000000000; ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32; return (ns); } #endif static void lock_prof_init_type(struct lock_prof_type *type) { int i; SLIST_INIT(&type->lpt_lpalloc); LIST_INIT(&type->lpt_lpoalloc); for (i = 0; i < LPROF_CACHE_SIZE; i++) { SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i], link); LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i], lpo_link); } } static void lock_prof_init(void *arg) { int cpu; for (cpu = 0; cpu <= mp_maxid; cpu++) { lp_cpu[cpu] = malloc(sizeof(*lp_cpu[cpu]), M_DEVBUF, M_WAITOK | M_ZERO); lock_prof_init_type(&lp_cpu[cpu]->lpc_types[0]); lock_prof_init_type(&lp_cpu[cpu]->lpc_types[1]); } } SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL); /* * To be certain that lock profiling has idled on all cpus before we * reset, we schedule the resetting thread on all active cpus. Since * all operations happen within critical sections we can be sure that * it is safe to zero the profiling structures. */ static void lock_prof_idle(void) { struct thread *td; int cpu; td = curthread; thread_lock(td); CPU_FOREACH(cpu) { sched_bind(td, cpu); } sched_unbind(td); thread_unlock(td); } static void lock_prof_reset_wait(void) { /* * Spin relinquishing our cpu so that lock_prof_idle may * run on it. */ while (lock_prof_resetting) sched_relinquish(curthread); } static void lock_prof_reset(void) { struct lock_prof_cpu *lpc; int enabled, i, cpu; /* * We not only race with acquiring and releasing locks but also * thread exit. To be certain that threads exit without valid head * pointers they must see resetting set before enabled is cleared. * Otherwise a lock may not be removed from a per-thread list due * to disabled being set but not wait for reset() to remove it below. */ atomic_store_rel_int(&lock_prof_resetting, 1); enabled = lock_prof_enable; lock_prof_enable = 0; lock_prof_idle(); /* * Some objects may have migrated between CPUs. Clear all links * before we zero the structures. Some items may still be linked * into per-thread lists as well. */ for (cpu = 0; cpu <= mp_maxid; cpu++) { lpc = lp_cpu[cpu]; for (i = 0; i < LPROF_CACHE_SIZE; i++) { LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link); LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link); } } for (cpu = 0; cpu <= mp_maxid; cpu++) { lpc = lp_cpu[cpu]; bzero(lpc, sizeof(*lpc)); lock_prof_init_type(&lpc->lpc_types[0]); lock_prof_init_type(&lpc->lpc_types[1]); } atomic_store_rel_int(&lock_prof_resetting, 0); lock_prof_enable = enabled; } static void lock_prof_output(struct lock_prof *lp, struct sbuf *sb) { const char *p; for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3); sbuf_printf(sb, "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n", lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000, lp->cnt_wait / 1000, lp->cnt_cur, lp->cnt_cur == 0 ? (uintmax_t)0 : lp->cnt_tot / (lp->cnt_cur * 1000), lp->cnt_cur == 0 ? (uintmax_t)0 : lp->cnt_wait / (lp->cnt_cur * 1000), (uintmax_t)0, lp->cnt_contest_locking, p, lp->line, lp->class->lc_name, lp->name); } static void lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash, int spin, int t) { struct lock_prof_type *type; struct lock_prof *l; int cpu; dst->file = match->file; dst->line = match->line; dst->class = match->class; dst->name = match->name; for (cpu = 0; cpu <= mp_maxid; cpu++) { if (lp_cpu[cpu] == NULL) continue; type = &lp_cpu[cpu]->lpc_types[spin]; SLIST_FOREACH(l, &type->lpt_hash[hash], link) { if (l->ticks == t) continue; if (l->file != match->file || l->line != match->line || l->name != match->name) continue; l->ticks = t; if (l->cnt_max > dst->cnt_max) dst->cnt_max = l->cnt_max; if (l->cnt_wait_max > dst->cnt_wait_max) dst->cnt_wait_max = l->cnt_wait_max; dst->cnt_tot += l->cnt_tot; dst->cnt_wait += l->cnt_wait; dst->cnt_cur += l->cnt_cur; dst->cnt_contest_locking += l->cnt_contest_locking; } } } static void lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin, int t) { struct lock_prof *l; int i; for (i = 0; i < LPROF_HASH_SIZE; ++i) { SLIST_FOREACH(l, &type->lpt_hash[i], link) { struct lock_prof lp = {}; if (l->ticks == t) continue; lock_prof_sum(l, &lp, i, spin, t); lock_prof_output(&lp, sb); } } } static int dump_lock_prof_stats(SYSCTL_HANDLER_ARGS) { struct sbuf *sb; int error, cpu, t; int enabled; error = sysctl_wire_old_buffer(req, 0); if (error != 0) return (error); sb = sbuf_new_for_sysctl(NULL, NULL, LPROF_SBUF_SIZE, req); sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n", "max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name"); enabled = lock_prof_enable; lock_prof_enable = 0; lock_prof_idle(); t = ticks; for (cpu = 0; cpu <= mp_maxid; cpu++) { if (lp_cpu[cpu] == NULL) continue; lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[0], sb, 0, t); lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[1], sb, 1, t); } lock_prof_enable = enabled; error = sbuf_finish(sb); /* Output a trailing NUL. */ if (error == 0) error = SYSCTL_OUT(req, "", 1); sbuf_delete(sb); return (error); } static int enable_lock_prof(SYSCTL_HANDLER_ARGS) { int error, v; v = lock_prof_enable; error = sysctl_handle_int(oidp, &v, v, req); if (error) return (error); if (req->newptr == NULL) return (error); if (v == lock_prof_enable) return (0); if (v == 1) lock_prof_reset(); lock_prof_enable = !!v; return (0); } static int reset_lock_prof_stats(SYSCTL_HANDLER_ARGS) { int error, v; v = 0; error = sysctl_handle_int(oidp, &v, 0, req); if (error) return (error); if (req->newptr == NULL) return (error); if (v == 0) return (0); lock_prof_reset(); return (0); } static struct lock_prof * lock_profile_lookup(struct lock_object *lo, int spin, const char *file, int line) { const char *unknown = "(unknown)"; struct lock_prof_type *type; struct lock_prof *lp; struct lphead *head; const char *p; u_int hash; p = file; if (p == NULL || *p == '\0') p = unknown; hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line; hash &= LPROF_HASH_MASK; type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; head = &type->lpt_hash[hash]; SLIST_FOREACH(lp, head, link) { if (lp->line == line && lp->file == p && lp->name == lo->lo_name) return (lp); } lp = SLIST_FIRST(&type->lpt_lpalloc); if (lp == NULL) { lock_prof_rejected++; return (lp); } SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link); lp->file = p; lp->line = line; lp->class = LOCK_CLASS(lo); lp->name = lo->lo_name; SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link); return (lp); } static struct lock_profile_object * lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file, int line) { struct lock_profile_object *l; struct lock_prof_type *type; struct lpohead *head; head = &curthread->td_lprof[spin]; LIST_FOREACH(l, head, lpo_link) if (l->lpo_obj == lo && l->lpo_file == file && l->lpo_line == line) return (l); type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; l = LIST_FIRST(&type->lpt_lpoalloc); if (l == NULL) { lock_prof_rejected++; return (NULL); } LIST_REMOVE(l, lpo_link); l->lpo_obj = lo; l->lpo_file = file; l->lpo_line = line; l->lpo_cnt = 0; LIST_INSERT_HEAD(head, l, lpo_link); return (l); } void lock_profile_obtain_lock_success(struct lock_object *lo, int contested, uint64_t waittime, const char *file, int line) { static int lock_prof_count; struct lock_profile_object *l; int spin; + if (SCHEDULER_STOPPED()) + return; + /* don't reset the timer when/if recursing */ if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) return; if (lock_prof_skipcount && (++lock_prof_count % lock_prof_skipcount) != 0) return; spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; if (spin && lock_prof_skipspin == 1) return; critical_enter(); /* Recheck enabled now that we're in a critical section. */ if (lock_prof_enable == 0) goto out; l = lock_profile_object_lookup(lo, spin, file, line); if (l == NULL) goto out; l->lpo_cnt++; if (++l->lpo_ref > 1) goto out; l->lpo_contest_locking = contested; l->lpo_acqtime = nanoseconds(); if (waittime && (l->lpo_acqtime > waittime)) l->lpo_waittime = l->lpo_acqtime - waittime; else l->lpo_waittime = 0; out: critical_exit(); } void lock_profile_thread_exit(struct thread *td) { #ifdef INVARIANTS struct lock_profile_object *l; MPASS(curthread->td_critnest == 0); #endif /* * If lock profiling was disabled we have to wait for reset to * clear our pointers before we can exit safely. */ lock_prof_reset_wait(); #ifdef INVARIANTS LIST_FOREACH(l, &td->td_lprof[0], lpo_link) printf("thread still holds lock acquired at %s:%d\n", l->lpo_file, l->lpo_line); LIST_FOREACH(l, &td->td_lprof[1], lpo_link) printf("thread still holds lock acquired at %s:%d\n", l->lpo_file, l->lpo_line); #endif MPASS(LIST_FIRST(&td->td_lprof[0]) == NULL); MPASS(LIST_FIRST(&td->td_lprof[1]) == NULL); } void lock_profile_release_lock(struct lock_object *lo) { struct lock_profile_object *l; struct lock_prof_type *type; struct lock_prof *lp; uint64_t curtime, holdtime; struct lpohead *head; int spin; + if (SCHEDULER_STOPPED()) + return; if (lo->lo_flags & LO_NOPROFILE) return; spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; head = &curthread->td_lprof[spin]; if (LIST_FIRST(head) == NULL) return; critical_enter(); /* Recheck enabled now that we're in a critical section. */ if (lock_prof_enable == 0 && lock_prof_resetting == 1) goto out; /* * If lock profiling is not enabled we still want to remove the * lpo from our queue. */ LIST_FOREACH(l, head, lpo_link) if (l->lpo_obj == lo) break; if (l == NULL) goto out; if (--l->lpo_ref > 0) goto out; lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line); if (lp == NULL) goto release; curtime = nanoseconds(); if (curtime < l->lpo_acqtime) goto release; holdtime = curtime - l->lpo_acqtime; /* * Record if the lock has been held longer now than ever * before. */ if (holdtime > lp->cnt_max) lp->cnt_max = holdtime; if (l->lpo_waittime > lp->cnt_wait_max) lp->cnt_wait_max = l->lpo_waittime; lp->cnt_tot += holdtime; lp->cnt_wait += l->lpo_waittime; lp->cnt_contest_locking += l->lpo_contest_locking; lp->cnt_cur += l->lpo_cnt; release: LIST_REMOVE(l, lpo_link); type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link); out: critical_exit(); } static SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging"); static SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL, "lock profiling"); SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipcount, CTLFLAG_RW, &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions."); SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, &lock_prof_rejected, 0, "Number of rejected profiling records"); SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics"); SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW, NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics"); SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW, NULL, 0, enable_lock_prof, "I", "Enable lock profiling"); #endif Index: head/sys/kern/subr_witness.c =================================================================== --- head/sys/kern/subr_witness.c (revision 228423) +++ head/sys/kern/subr_witness.c (revision 228424) @@ -1,2826 +1,2840 @@ /*- * Copyright (c) 2008 Isilon Systems, Inc. * Copyright (c) 2008 Ilya Maykov * Copyright (c) 1998 Berkeley Software Design, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Berkeley Software Design Inc's name may not be used to endorse or * promote products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $ * and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $ */ /* * Implementation of the `witness' lock verifier. Originally implemented for * mutexes in BSD/OS. Extended to handle generic lock objects and lock * classes in FreeBSD. */ /* * Main Entry: witness * Pronunciation: 'wit-n&s * Function: noun * Etymology: Middle English witnesse, from Old English witnes knowledge, * testimony, witness, from 2wit * Date: before 12th century * 1 : attestation of a fact or event : TESTIMONY * 2 : one that gives evidence; specifically : one who testifies in * a cause or before a judicial tribunal * 3 : one asked to be present at a transaction so as to be able to * testify to its having taken place * 4 : one who has personal knowledge of something * 5 a : something serving as evidence or proof : SIGN * b : public affirmation by word or example of usually * religious faith or conviction * 6 capitalized : a member of the Jehovah's Witnesses */ /* * Special rules concerning Giant and lock orders: * * 1) Giant must be acquired before any other mutexes. Stated another way, * no other mutex may be held when Giant is acquired. * * 2) Giant must be released when blocking on a sleepable lock. * * This rule is less obvious, but is a result of Giant providing the same * semantics as spl(). Basically, when a thread sleeps, it must release * Giant. When a thread blocks on a sleepable lock, it sleeps. Hence rule * 2). * * 3) Giant may be acquired before or after sleepable locks. * * This rule is also not quite as obvious. Giant may be acquired after * a sleepable lock because it is a non-sleepable lock and non-sleepable * locks may always be acquired while holding a sleepable lock. The second * case, Giant before a sleepable lock, follows from rule 2) above. Suppose * you have two threads T1 and T2 and a sleepable lock X. Suppose that T1 * acquires X and blocks on Giant. Then suppose that T2 acquires Giant and * blocks on X. When T2 blocks on X, T2 will release Giant allowing T1 to * execute. Thus, acquiring Giant both before and after a sleepable lock * will not result in a lock order reversal. */ #include __FBSDID("$FreeBSD$"); #include "opt_ddb.h" #include "opt_hwpmc_hooks.h" #include "opt_stack.h" #include "opt_witness.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DDB #include #endif #include #if !defined(DDB) && !defined(STACK) #error "DDB or STACK options are required for WITNESS" #endif /* Note that these traces do not work with KTR_ALQ. */ #if 0 #define KTR_WITNESS KTR_SUBSYS #else #define KTR_WITNESS 0 #endif #define LI_RECURSEMASK 0x0000ffff /* Recursion depth of lock instance. */ #define LI_EXCLUSIVE 0x00010000 /* Exclusive lock instance. */ #define LI_NORELEASE 0x00020000 /* Lock not allowed to be released. */ /* Define this to check for blessed mutexes */ #undef BLESSING #define WITNESS_COUNT 1024 #define WITNESS_CHILDCOUNT (WITNESS_COUNT * 4) #define WITNESS_HASH_SIZE 251 /* Prime, gives load factor < 2 */ #define WITNESS_PENDLIST 768 /* Allocate 256 KB of stack data space */ #define WITNESS_LO_DATA_COUNT 2048 /* Prime, gives load factor of ~2 at full load */ #define WITNESS_LO_HASH_SIZE 1021 /* * XXX: This is somewhat bogus, as we assume here that at most 2048 threads * will hold LOCK_NCHILDREN locks. We handle failure ok, and we should * probably be safe for the most part, but it's still a SWAG. */ #define LOCK_NCHILDREN 5 #define LOCK_CHILDCOUNT 2048 #define MAX_W_NAME 64 #define BADSTACK_SBUF_SIZE (256 * WITNESS_COUNT) #define FULLGRAPH_SBUF_SIZE 512 /* * These flags go in the witness relationship matrix and describe the * relationship between any two struct witness objects. */ #define WITNESS_UNRELATED 0x00 /* No lock order relation. */ #define WITNESS_PARENT 0x01 /* Parent, aka direct ancestor. */ #define WITNESS_ANCESTOR 0x02 /* Direct or indirect ancestor. */ #define WITNESS_CHILD 0x04 /* Child, aka direct descendant. */ #define WITNESS_DESCENDANT 0x08 /* Direct or indirect descendant. */ #define WITNESS_ANCESTOR_MASK (WITNESS_PARENT | WITNESS_ANCESTOR) #define WITNESS_DESCENDANT_MASK (WITNESS_CHILD | WITNESS_DESCENDANT) #define WITNESS_RELATED_MASK \ (WITNESS_ANCESTOR_MASK | WITNESS_DESCENDANT_MASK) #define WITNESS_REVERSAL 0x10 /* A lock order reversal has been * observed. */ #define WITNESS_RESERVED1 0x20 /* Unused flag, reserved. */ #define WITNESS_RESERVED2 0x40 /* Unused flag, reserved. */ #define WITNESS_LOCK_ORDER_KNOWN 0x80 /* This lock order is known. */ /* Descendant to ancestor flags */ #define WITNESS_DTOA(x) (((x) & WITNESS_RELATED_MASK) >> 2) /* Ancestor to descendant flags */ #define WITNESS_ATOD(x) (((x) & WITNESS_RELATED_MASK) << 2) #define WITNESS_INDEX_ASSERT(i) \ MPASS((i) > 0 && (i) <= w_max_used_index && (i) < WITNESS_COUNT) static MALLOC_DEFINE(M_WITNESS, "Witness", "Witness"); /* * Lock instances. A lock instance is the data associated with a lock while * it is held by witness. For example, a lock instance will hold the * recursion count of a lock. Lock instances are held in lists. Spin locks * are held in a per-cpu list while sleep locks are held in per-thread list. */ struct lock_instance { struct lock_object *li_lock; const char *li_file; int li_line; u_int li_flags; }; /* * A simple list type used to build the list of locks held by a thread * or CPU. We can't simply embed the list in struct lock_object since a * lock may be held by more than one thread if it is a shared lock. Locks * are added to the head of the list, so we fill up each list entry from * "the back" logically. To ease some of the arithmetic, we actually fill * in each list entry the normal way (children[0] then children[1], etc.) but * when we traverse the list we read children[count-1] as the first entry * down to children[0] as the final entry. */ struct lock_list_entry { struct lock_list_entry *ll_next; struct lock_instance ll_children[LOCK_NCHILDREN]; u_int ll_count; }; /* * The main witness structure. One of these per named lock type in the system * (for example, "vnode interlock"). */ struct witness { char w_name[MAX_W_NAME]; uint32_t w_index; /* Index in the relationship matrix */ struct lock_class *w_class; STAILQ_ENTRY(witness) w_list; /* List of all witnesses. */ STAILQ_ENTRY(witness) w_typelist; /* Witnesses of a type. */ struct witness *w_hash_next; /* Linked list in hash buckets. */ const char *w_file; /* File where last acquired */ uint32_t w_line; /* Line where last acquired */ uint32_t w_refcount; uint16_t w_num_ancestors; /* direct/indirect * ancestor count */ uint16_t w_num_descendants; /* direct/indirect * descendant count */ int16_t w_ddb_level; unsigned w_displayed:1; unsigned w_reversed:1; }; STAILQ_HEAD(witness_list, witness); /* * The witness hash table. Keys are witness names (const char *), elements are * witness objects (struct witness *). */ struct witness_hash { struct witness *wh_array[WITNESS_HASH_SIZE]; uint32_t wh_size; uint32_t wh_count; }; /* * Key type for the lock order data hash table. */ struct witness_lock_order_key { uint16_t from; uint16_t to; }; struct witness_lock_order_data { struct stack wlod_stack; struct witness_lock_order_key wlod_key; struct witness_lock_order_data *wlod_next; }; /* * The witness lock order data hash table. Keys are witness index tuples * (struct witness_lock_order_key), elements are lock order data objects * (struct witness_lock_order_data). */ struct witness_lock_order_hash { struct witness_lock_order_data *wloh_array[WITNESS_LO_HASH_SIZE]; u_int wloh_size; u_int wloh_count; }; #ifdef BLESSING struct witness_blessed { const char *b_lock1; const char *b_lock2; }; #endif struct witness_pendhelp { const char *wh_type; struct lock_object *wh_lock; }; struct witness_order_list_entry { const char *w_name; struct lock_class *w_class; }; /* * Returns 0 if one of the locks is a spin lock and the other is not. * Returns 1 otherwise. */ static __inline int witness_lock_type_equal(struct witness *w1, struct witness *w2) { return ((w1->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) == (w2->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))); } static __inline int witness_lock_order_key_empty(const struct witness_lock_order_key *key) { return (key->from == 0 && key->to == 0); } static __inline int witness_lock_order_key_equal(const struct witness_lock_order_key *a, const struct witness_lock_order_key *b) { return (a->from == b->from && a->to == b->to); } static int _isitmyx(struct witness *w1, struct witness *w2, int rmask, const char *fname); #ifdef KDB static void _witness_debugger(int cond, const char *msg); #endif static void adopt(struct witness *parent, struct witness *child); #ifdef BLESSING static int blessed(struct witness *, struct witness *); #endif static void depart(struct witness *w); static struct witness *enroll(const char *description, struct lock_class *lock_class); static struct lock_instance *find_instance(struct lock_list_entry *list, const struct lock_object *lock); static int isitmychild(struct witness *parent, struct witness *child); static int isitmydescendant(struct witness *parent, struct witness *child); static void itismychild(struct witness *parent, struct witness *child); static int sysctl_debug_witness_badstacks(SYSCTL_HANDLER_ARGS); static int sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS); static int sysctl_debug_witness_fullgraph(SYSCTL_HANDLER_ARGS); static void witness_add_fullgraph(struct sbuf *sb, struct witness *parent); #ifdef DDB static void witness_ddb_compute_levels(void); static void witness_ddb_display(int(*)(const char *fmt, ...)); static void witness_ddb_display_descendants(int(*)(const char *fmt, ...), struct witness *, int indent); static void witness_ddb_display_list(int(*prnt)(const char *fmt, ...), struct witness_list *list); static void witness_ddb_level_descendants(struct witness *parent, int l); static void witness_ddb_list(struct thread *td); #endif static void witness_free(struct witness *m); static struct witness *witness_get(void); static uint32_t witness_hash_djb2(const uint8_t *key, uint32_t size); static struct witness *witness_hash_get(const char *key); static void witness_hash_put(struct witness *w); static void witness_init_hash_tables(void); static void witness_increment_graph_generation(void); static void witness_lock_list_free(struct lock_list_entry *lle); static struct lock_list_entry *witness_lock_list_get(void); static int witness_lock_order_add(struct witness *parent, struct witness *child); static int witness_lock_order_check(struct witness *parent, struct witness *child); static struct witness_lock_order_data *witness_lock_order_get( struct witness *parent, struct witness *child); static void witness_list_lock(struct lock_instance *instance, int (*prnt)(const char *fmt, ...)); static void witness_setflag(struct lock_object *lock, int flag, int set); #ifdef KDB #define witness_debugger(c) _witness_debugger(c, __func__) #else #define witness_debugger(c) #endif static SYSCTL_NODE(_debug, OID_AUTO, witness, CTLFLAG_RW, NULL, "Witness Locking"); /* * If set to 0, lock order checking is disabled. If set to -1, * witness is completely disabled. Otherwise witness performs full * lock order checking for all locks. At runtime, lock order checking * may be toggled. However, witness cannot be reenabled once it is * completely disabled. */ static int witness_watch = 1; TUNABLE_INT("debug.witness.watch", &witness_watch); SYSCTL_PROC(_debug_witness, OID_AUTO, watch, CTLFLAG_RW | CTLTYPE_INT, NULL, 0, sysctl_debug_witness_watch, "I", "witness is watching lock operations"); #ifdef KDB /* * When KDB is enabled and witness_kdb is 1, it will cause the system * to drop into kdebug() when: * - a lock hierarchy violation occurs * - locks are held when going to sleep. */ #ifdef WITNESS_KDB int witness_kdb = 1; #else int witness_kdb = 0; #endif TUNABLE_INT("debug.witness.kdb", &witness_kdb); SYSCTL_INT(_debug_witness, OID_AUTO, kdb, CTLFLAG_RW, &witness_kdb, 0, ""); /* * When KDB is enabled and witness_trace is 1, it will cause the system * to print a stack trace: * - a lock hierarchy violation occurs * - locks are held when going to sleep. */ int witness_trace = 1; TUNABLE_INT("debug.witness.trace", &witness_trace); SYSCTL_INT(_debug_witness, OID_AUTO, trace, CTLFLAG_RW, &witness_trace, 0, ""); #endif /* KDB */ #ifdef WITNESS_SKIPSPIN int witness_skipspin = 1; #else int witness_skipspin = 0; #endif TUNABLE_INT("debug.witness.skipspin", &witness_skipspin); SYSCTL_INT(_debug_witness, OID_AUTO, skipspin, CTLFLAG_RDTUN, &witness_skipspin, 0, ""); /* * Call this to print out the relations between locks. */ SYSCTL_PROC(_debug_witness, OID_AUTO, fullgraph, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, sysctl_debug_witness_fullgraph, "A", "Show locks relation graphs"); /* * Call this to print out the witness faulty stacks. */ SYSCTL_PROC(_debug_witness, OID_AUTO, badstacks, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, sysctl_debug_witness_badstacks, "A", "Show bad witness stacks"); static struct mtx w_mtx; /* w_list */ static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); /* w_typelist */ static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); /* lock list */ static struct lock_list_entry *w_lock_list_free = NULL; static struct witness_pendhelp pending_locks[WITNESS_PENDLIST]; static u_int pending_cnt; static int w_free_cnt, w_spin_cnt, w_sleep_cnt; SYSCTL_INT(_debug_witness, OID_AUTO, free_cnt, CTLFLAG_RD, &w_free_cnt, 0, ""); SYSCTL_INT(_debug_witness, OID_AUTO, spin_cnt, CTLFLAG_RD, &w_spin_cnt, 0, ""); SYSCTL_INT(_debug_witness, OID_AUTO, sleep_cnt, CTLFLAG_RD, &w_sleep_cnt, 0, ""); static struct witness *w_data; static uint8_t w_rmatrix[WITNESS_COUNT+1][WITNESS_COUNT+1]; static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; static struct witness_hash w_hash; /* The witness hash table. */ /* The lock order data hash */ static struct witness_lock_order_data w_lodata[WITNESS_LO_DATA_COUNT]; static struct witness_lock_order_data *w_lofree = NULL; static struct witness_lock_order_hash w_lohash; static int w_max_used_index = 0; static unsigned int w_generation = 0; static const char w_notrunning[] = "Witness not running\n"; static const char w_stillcold[] = "Witness is still cold\n"; static struct witness_order_list_entry order_lists[] = { /* * sx locks */ { "proctree", &lock_class_sx }, { "allproc", &lock_class_sx }, { "allprison", &lock_class_sx }, { NULL, NULL }, /* * Various mutexes */ { "Giant", &lock_class_mtx_sleep }, { "pipe mutex", &lock_class_mtx_sleep }, { "sigio lock", &lock_class_mtx_sleep }, { "process group", &lock_class_mtx_sleep }, { "process lock", &lock_class_mtx_sleep }, { "session", &lock_class_mtx_sleep }, { "uidinfo hash", &lock_class_rw }, #ifdef HWPMC_HOOKS { "pmc-sleep", &lock_class_mtx_sleep }, #endif { "time lock", &lock_class_mtx_sleep }, { NULL, NULL }, /* * Sockets */ { "accept", &lock_class_mtx_sleep }, { "so_snd", &lock_class_mtx_sleep }, { "so_rcv", &lock_class_mtx_sleep }, { "sellck", &lock_class_mtx_sleep }, { NULL, NULL }, /* * Routing */ { "so_rcv", &lock_class_mtx_sleep }, { "radix node head", &lock_class_rw }, { "rtentry", &lock_class_mtx_sleep }, { "ifaddr", &lock_class_mtx_sleep }, { NULL, NULL }, /* * IPv4 multicast: * protocol locks before interface locks, after UDP locks. */ { "udpinp", &lock_class_rw }, { "in_multi_mtx", &lock_class_mtx_sleep }, { "igmp_mtx", &lock_class_mtx_sleep }, { "if_addr_mtx", &lock_class_mtx_sleep }, { NULL, NULL }, /* * IPv6 multicast: * protocol locks before interface locks, after UDP locks. */ { "udpinp", &lock_class_rw }, { "in6_multi_mtx", &lock_class_mtx_sleep }, { "mld_mtx", &lock_class_mtx_sleep }, { "if_addr_mtx", &lock_class_mtx_sleep }, { NULL, NULL }, /* * UNIX Domain Sockets */ { "unp_global_rwlock", &lock_class_rw }, { "unp_list_lock", &lock_class_mtx_sleep }, { "unp", &lock_class_mtx_sleep }, { "so_snd", &lock_class_mtx_sleep }, { NULL, NULL }, /* * UDP/IP */ { "udp", &lock_class_rw }, { "udpinp", &lock_class_rw }, { "so_snd", &lock_class_mtx_sleep }, { NULL, NULL }, /* * TCP/IP */ { "tcp", &lock_class_rw }, { "tcpinp", &lock_class_rw }, { "so_snd", &lock_class_mtx_sleep }, { NULL, NULL }, /* * netatalk */ { "ddp_list_mtx", &lock_class_mtx_sleep }, { "ddp_mtx", &lock_class_mtx_sleep }, { NULL, NULL }, /* * BPF */ { "bpf global lock", &lock_class_mtx_sleep }, { "bpf interface lock", &lock_class_mtx_sleep }, { "bpf cdev lock", &lock_class_mtx_sleep }, { NULL, NULL }, /* * NFS server */ { "nfsd_mtx", &lock_class_mtx_sleep }, { "so_snd", &lock_class_mtx_sleep }, { NULL, NULL }, /* * IEEE 802.11 */ { "802.11 com lock", &lock_class_mtx_sleep}, { NULL, NULL }, /* * Network drivers */ { "network driver", &lock_class_mtx_sleep}, { NULL, NULL }, /* * Netgraph */ { "ng_node", &lock_class_mtx_sleep }, { "ng_worklist", &lock_class_mtx_sleep }, { NULL, NULL }, /* * CDEV */ { "system map", &lock_class_mtx_sleep }, { "vm page queue mutex", &lock_class_mtx_sleep }, { "vnode interlock", &lock_class_mtx_sleep }, { "cdev", &lock_class_mtx_sleep }, { NULL, NULL }, /* * VM * */ { "vm object", &lock_class_mtx_sleep }, { "page lock", &lock_class_mtx_sleep }, { "vm page queue mutex", &lock_class_mtx_sleep }, { "pmap", &lock_class_mtx_sleep }, { NULL, NULL }, /* * kqueue/VFS interaction */ { "kqueue", &lock_class_mtx_sleep }, { "struct mount mtx", &lock_class_mtx_sleep }, { "vnode interlock", &lock_class_mtx_sleep }, { NULL, NULL }, /* * ZFS locking */ { "dn->dn_mtx", &lock_class_sx }, { "dr->dt.di.dr_mtx", &lock_class_sx }, { "db->db_mtx", &lock_class_sx }, { NULL, NULL }, /* * spin locks */ #ifdef SMP { "ap boot", &lock_class_mtx_spin }, #endif { "rm.mutex_mtx", &lock_class_mtx_spin }, { "sio", &lock_class_mtx_spin }, { "scrlock", &lock_class_mtx_spin }, #ifdef __i386__ { "cy", &lock_class_mtx_spin }, #endif #ifdef __sparc64__ { "pcib_mtx", &lock_class_mtx_spin }, { "rtc_mtx", &lock_class_mtx_spin }, #endif { "scc_hwmtx", &lock_class_mtx_spin }, { "uart_hwmtx", &lock_class_mtx_spin }, { "fast_taskqueue", &lock_class_mtx_spin }, { "intr table", &lock_class_mtx_spin }, #ifdef HWPMC_HOOKS { "pmc-per-proc", &lock_class_mtx_spin }, #endif { "process slock", &lock_class_mtx_spin }, { "sleepq chain", &lock_class_mtx_spin }, { "umtx lock", &lock_class_mtx_spin }, { "rm_spinlock", &lock_class_mtx_spin }, { "turnstile chain", &lock_class_mtx_spin }, { "turnstile lock", &lock_class_mtx_spin }, { "sched lock", &lock_class_mtx_spin }, { "td_contested", &lock_class_mtx_spin }, { "callout", &lock_class_mtx_spin }, { "entropy harvest mutex", &lock_class_mtx_spin }, { "syscons video lock", &lock_class_mtx_spin }, #ifdef SMP { "smp rendezvous", &lock_class_mtx_spin }, #endif #ifdef __powerpc__ { "tlb0", &lock_class_mtx_spin }, #endif /* * leaf locks */ { "intrcnt", &lock_class_mtx_spin }, { "icu", &lock_class_mtx_spin }, #if defined(SMP) && defined(__sparc64__) { "ipi", &lock_class_mtx_spin }, #endif #ifdef __i386__ { "allpmaps", &lock_class_mtx_spin }, { "descriptor tables", &lock_class_mtx_spin }, #endif { "clk", &lock_class_mtx_spin }, { "cpuset", &lock_class_mtx_spin }, { "mprof lock", &lock_class_mtx_spin }, { "zombie lock", &lock_class_mtx_spin }, { "ALD Queue", &lock_class_mtx_spin }, #ifdef __ia64__ { "MCA spin lock", &lock_class_mtx_spin }, #endif #if defined(__i386__) || defined(__amd64__) { "pcicfg", &lock_class_mtx_spin }, { "NDIS thread lock", &lock_class_mtx_spin }, #endif { "tw_osl_io_lock", &lock_class_mtx_spin }, { "tw_osl_q_lock", &lock_class_mtx_spin }, { "tw_cl_io_lock", &lock_class_mtx_spin }, { "tw_cl_intr_lock", &lock_class_mtx_spin }, { "tw_cl_gen_lock", &lock_class_mtx_spin }, #ifdef HWPMC_HOOKS { "pmc-leaf", &lock_class_mtx_spin }, #endif { "blocked lock", &lock_class_mtx_spin }, { NULL, NULL }, { NULL, NULL } }; #ifdef BLESSING /* * Pairs of locks which have been blessed * Don't complain about order problems with blessed locks */ static struct witness_blessed blessed_list[] = { }; static int blessed_count = sizeof(blessed_list) / sizeof(struct witness_blessed); #endif /* * This global is set to 0 once it becomes safe to use the witness code. */ static int witness_cold = 1; /* * This global is set to 1 once the static lock orders have been enrolled * so that a warning can be issued for any spin locks enrolled later. */ static int witness_spin_warn = 0; /* Trim useless garbage from filenames. */ static const char * fixup_filename(const char *file) { if (file == NULL) return (NULL); while (strncmp(file, "../", 3) == 0) file += 3; return (file); } /* * The WITNESS-enabled diagnostic code. Note that the witness code does * assume that the early boot is single-threaded at least until after this * routine is completed. */ static void witness_initialize(void *dummy __unused) { struct lock_object *lock; struct witness_order_list_entry *order; struct witness *w, *w1; int i; w_data = malloc(sizeof (struct witness) * WITNESS_COUNT, M_WITNESS, M_NOWAIT | M_ZERO); /* * We have to release Giant before initializing its witness * structure so that WITNESS doesn't get confused. */ mtx_unlock(&Giant); mtx_assert(&Giant, MA_NOTOWNED); CTR1(KTR_WITNESS, "%s: initializing witness", __func__); mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET | MTX_NOWITNESS | MTX_NOPROFILE); for (i = WITNESS_COUNT - 1; i >= 0; i--) { w = &w_data[i]; memset(w, 0, sizeof(*w)); w_data[i].w_index = i; /* Witness index never changes. */ witness_free(w); } KASSERT(STAILQ_FIRST(&w_free)->w_index == 0, ("%s: Invalid list of free witness objects", __func__)); /* Witness with index 0 is not used to aid in debugging. */ STAILQ_REMOVE_HEAD(&w_free, w_list); w_free_cnt--; memset(w_rmatrix, 0, (sizeof(**w_rmatrix) * (WITNESS_COUNT+1) * (WITNESS_COUNT+1))); for (i = 0; i < LOCK_CHILDCOUNT; i++) witness_lock_list_free(&w_locklistdata[i]); witness_init_hash_tables(); /* First add in all the specified order lists. */ for (order = order_lists; order->w_name != NULL; order++) { w = enroll(order->w_name, order->w_class); if (w == NULL) continue; w->w_file = "order list"; for (order++; order->w_name != NULL; order++) { w1 = enroll(order->w_name, order->w_class); if (w1 == NULL) continue; w1->w_file = "order list"; itismychild(w, w1); w = w1; } } witness_spin_warn = 1; /* Iterate through all locks and add them to witness. */ for (i = 0; pending_locks[i].wh_lock != NULL; i++) { lock = pending_locks[i].wh_lock; KASSERT(lock->lo_flags & LO_WITNESS, ("%s: lock %s is on pending list but not LO_WITNESS", __func__, lock->lo_name)); lock->lo_witness = enroll(pending_locks[i].wh_type, LOCK_CLASS(lock)); } /* Mark the witness code as being ready for use. */ witness_cold = 0; mtx_lock(&Giant); } SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL); void witness_init(struct lock_object *lock, const char *type) { struct lock_class *class; /* Various sanity checks. */ class = LOCK_CLASS(lock); if ((lock->lo_flags & LO_RECURSABLE) != 0 && (class->lc_flags & LC_RECURSABLE) == 0) panic("%s: lock (%s) %s can not be recursable", __func__, class->lc_name, lock->lo_name); if ((lock->lo_flags & LO_SLEEPABLE) != 0 && (class->lc_flags & LC_SLEEPABLE) == 0) panic("%s: lock (%s) %s can not be sleepable", __func__, class->lc_name, lock->lo_name); if ((lock->lo_flags & LO_UPGRADABLE) != 0 && (class->lc_flags & LC_UPGRADABLE) == 0) panic("%s: lock (%s) %s can not be upgradable", __func__, class->lc_name, lock->lo_name); /* * If we shouldn't watch this lock, then just clear lo_witness. * Otherwise, if witness_cold is set, then it is too early to * enroll this lock, so defer it to witness_initialize() by adding * it to the pending_locks list. If it is not too early, then enroll * the lock now. */ if (witness_watch < 1 || panicstr != NULL || (lock->lo_flags & LO_WITNESS) == 0) lock->lo_witness = NULL; else if (witness_cold) { pending_locks[pending_cnt].wh_lock = lock; pending_locks[pending_cnt++].wh_type = type; if (pending_cnt > WITNESS_PENDLIST) panic("%s: pending locks list is too small, bump it\n", __func__); } else lock->lo_witness = enroll(type, class); } void witness_destroy(struct lock_object *lock) { struct lock_class *class; struct witness *w; class = LOCK_CLASS(lock); if (witness_cold) panic("lock (%s) %s destroyed while witness_cold", class->lc_name, lock->lo_name); /* XXX: need to verify that no one holds the lock */ if ((lock->lo_flags & LO_WITNESS) == 0 || lock->lo_witness == NULL) return; w = lock->lo_witness; mtx_lock_spin(&w_mtx); MPASS(w->w_refcount > 0); w->w_refcount--; if (w->w_refcount == 0) depart(w); mtx_unlock_spin(&w_mtx); } #ifdef DDB static void witness_ddb_compute_levels(void) { struct witness *w; /* * First clear all levels. */ STAILQ_FOREACH(w, &w_all, w_list) w->w_ddb_level = -1; /* * Look for locks with no parents and level all their descendants. */ STAILQ_FOREACH(w, &w_all, w_list) { /* If the witness has ancestors (is not a root), skip it. */ if (w->w_num_ancestors > 0) continue; witness_ddb_level_descendants(w, 0); } } static void witness_ddb_level_descendants(struct witness *w, int l) { int i; if (w->w_ddb_level >= l) return; w->w_ddb_level = l; l++; for (i = 1; i <= w_max_used_index; i++) { if (w_rmatrix[w->w_index][i] & WITNESS_PARENT) witness_ddb_level_descendants(&w_data[i], l); } } static void witness_ddb_display_descendants(int(*prnt)(const char *fmt, ...), struct witness *w, int indent) { int i; for (i = 0; i < indent; i++) prnt(" "); prnt("%s (type: %s, depth: %d, active refs: %d)", w->w_name, w->w_class->lc_name, w->w_ddb_level, w->w_refcount); if (w->w_displayed) { prnt(" -- (already displayed)\n"); return; } w->w_displayed = 1; if (w->w_file != NULL && w->w_line != 0) prnt(" -- last acquired @ %s:%d\n", fixup_filename(w->w_file), w->w_line); else prnt(" -- never acquired\n"); indent++; WITNESS_INDEX_ASSERT(w->w_index); for (i = 1; i <= w_max_used_index; i++) { if (w_rmatrix[w->w_index][i] & WITNESS_PARENT) witness_ddb_display_descendants(prnt, &w_data[i], indent); } } static void witness_ddb_display_list(int(*prnt)(const char *fmt, ...), struct witness_list *list) { struct witness *w; STAILQ_FOREACH(w, list, w_typelist) { if (w->w_file == NULL || w->w_ddb_level > 0) continue; /* This lock has no anscestors - display its descendants. */ witness_ddb_display_descendants(prnt, w, 0); } } static void witness_ddb_display(int(*prnt)(const char *fmt, ...)) { struct witness *w; KASSERT(witness_cold == 0, ("%s: witness_cold", __func__)); witness_ddb_compute_levels(); /* Clear all the displayed flags. */ STAILQ_FOREACH(w, &w_all, w_list) w->w_displayed = 0; /* * First, handle sleep locks which have been acquired at least * once. */ prnt("Sleep locks:\n"); witness_ddb_display_list(prnt, &w_sleep); /* * Now do spin locks which have been acquired at least once. */ prnt("\nSpin locks:\n"); witness_ddb_display_list(prnt, &w_spin); /* * Finally, any locks which have not been acquired yet. */ prnt("\nLocks which were never acquired:\n"); STAILQ_FOREACH(w, &w_all, w_list) { if (w->w_file != NULL || w->w_refcount == 0) continue; prnt("%s (type: %s, depth: %d)\n", w->w_name, w->w_class->lc_name, w->w_ddb_level); } } #endif /* DDB */ int witness_defineorder(struct lock_object *lock1, struct lock_object *lock2) { if (witness_watch == -1 || panicstr != NULL) return (0); /* Require locks that witness knows about. */ if (lock1 == NULL || lock1->lo_witness == NULL || lock2 == NULL || lock2->lo_witness == NULL) return (EINVAL); mtx_assert(&w_mtx, MA_NOTOWNED); mtx_lock_spin(&w_mtx); /* * If we already have either an explicit or implied lock order that * is the other way around, then return an error. */ if (witness_watch && isitmydescendant(lock2->lo_witness, lock1->lo_witness)) { mtx_unlock_spin(&w_mtx); return (EDOOFUS); } /* Try to add the new order. */ CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, lock2->lo_witness->w_name, lock1->lo_witness->w_name); itismychild(lock1->lo_witness, lock2->lo_witness); mtx_unlock_spin(&w_mtx); return (0); } void witness_checkorder(struct lock_object *lock, int flags, const char *file, int line, struct lock_object *interlock) { struct lock_list_entry *lock_list, *lle; struct lock_instance *lock1, *lock2, *plock; struct lock_class *class; struct witness *w, *w1; struct thread *td; int i, j; if (witness_cold || witness_watch < 1 || lock->lo_witness == NULL || panicstr != NULL) return; w = lock->lo_witness; class = LOCK_CLASS(lock); td = curthread; if (class->lc_flags & LC_SLEEPLOCK) { /* * Since spin locks include a critical section, this check * implicitly enforces a lock order of all sleep locks before * all spin locks. */ if (td->td_critnest != 0 && !kdb_active) panic("blockable sleep lock (%s) %s @ %s:%d", class->lc_name, lock->lo_name, fixup_filename(file), line); /* * If this is the first lock acquired then just return as * no order checking is needed. */ lock_list = td->td_sleeplocks; if (lock_list == NULL || lock_list->ll_count == 0) return; } else { /* * If this is the first lock, just return as no order * checking is needed. Avoid problems with thread * migration pinning the thread while checking if * spinlocks are held. If at least one spinlock is held * the thread is in a safe path and it is allowed to * unpin it. */ sched_pin(); lock_list = PCPU_GET(spinlocks); if (lock_list == NULL || lock_list->ll_count == 0) { sched_unpin(); return; } sched_unpin(); } /* * Check to see if we are recursing on a lock we already own. If * so, make sure that we don't mismatch exclusive and shared lock * acquires. */ lock1 = find_instance(lock_list, lock); if (lock1 != NULL) { if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && (flags & LOP_EXCLUSIVE) == 0) { printf("shared lock of (%s) %s @ %s:%d\n", class->lc_name, lock->lo_name, fixup_filename(file), line); printf("while exclusively locked from %s:%d\n", fixup_filename(lock1->li_file), lock1->li_line); panic("share->excl"); } if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && (flags & LOP_EXCLUSIVE) != 0) { printf("exclusive lock of (%s) %s @ %s:%d\n", class->lc_name, lock->lo_name, fixup_filename(file), line); printf("while share locked from %s:%d\n", fixup_filename(lock1->li_file), lock1->li_line); panic("excl->share"); } return; } /* * Find the previously acquired lock, but ignore interlocks. */ plock = &lock_list->ll_children[lock_list->ll_count - 1]; if (interlock != NULL && plock->li_lock == interlock) { if (lock_list->ll_count > 1) plock = &lock_list->ll_children[lock_list->ll_count - 2]; else { lle = lock_list->ll_next; /* * The interlock is the only lock we hold, so * simply return. */ if (lle == NULL) return; plock = &lle->ll_children[lle->ll_count - 1]; } } /* * Try to perform most checks without a lock. If this succeeds we * can skip acquiring the lock and return success. */ w1 = plock->li_lock->lo_witness; if (witness_lock_order_check(w1, w)) return; /* * Check for duplicate locks of the same type. Note that we only * have to check for this on the last lock we just acquired. Any * other cases will be caught as lock order violations. */ mtx_lock_spin(&w_mtx); witness_lock_order_add(w1, w); if (w1 == w) { i = w->w_index; if (!(lock->lo_flags & LO_DUPOK) && !(flags & LOP_DUPOK) && !(w_rmatrix[i][i] & WITNESS_REVERSAL)) { w_rmatrix[i][i] |= WITNESS_REVERSAL; w->w_reversed = 1; mtx_unlock_spin(&w_mtx); printf( "acquiring duplicate lock of same type: \"%s\"\n", w->w_name); printf(" 1st %s @ %s:%d\n", plock->li_lock->lo_name, fixup_filename(plock->li_file), plock->li_line); printf(" 2nd %s @ %s:%d\n", lock->lo_name, fixup_filename(file), line); witness_debugger(1); } else mtx_unlock_spin(&w_mtx); return; } mtx_assert(&w_mtx, MA_OWNED); /* * If we know that the lock we are acquiring comes after * the lock we most recently acquired in the lock order tree, * then there is no need for any further checks. */ if (isitmychild(w1, w)) goto out; for (j = 0, lle = lock_list; lle != NULL; lle = lle->ll_next) { for (i = lle->ll_count - 1; i >= 0; i--, j++) { MPASS(j < WITNESS_COUNT); lock1 = &lle->ll_children[i]; /* * Ignore the interlock the first time we see it. */ if (interlock != NULL && interlock == lock1->li_lock) { interlock = NULL; continue; } /* * If this lock doesn't undergo witness checking, * then skip it. */ w1 = lock1->li_lock->lo_witness; if (w1 == NULL) { KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, ("lock missing witness structure")); continue; } /* * If we are locking Giant and this is a sleepable * lock, then skip it. */ if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0 && lock == &Giant.lock_object) continue; /* * If we are locking a sleepable lock and this lock * is Giant, then skip it. */ if ((lock->lo_flags & LO_SLEEPABLE) != 0 && lock1->li_lock == &Giant.lock_object) continue; /* * If we are locking a sleepable lock and this lock * isn't sleepable, we want to treat it as a lock * order violation to enfore a general lock order of * sleepable locks before non-sleepable locks. */ if (((lock->lo_flags & LO_SLEEPABLE) != 0 && (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) goto reversal; /* * If we are locking Giant and this is a non-sleepable * lock, then treat it as a reversal. */ if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 && lock == &Giant.lock_object) goto reversal; /* * Check the lock order hierarchy for a reveresal. */ if (!isitmydescendant(w, w1)) continue; reversal: /* * We have a lock order violation, check to see if it * is allowed or has already been yelled about. */ #ifdef BLESSING /* * If the lock order is blessed, just bail. We don't * look for other lock order violations though, which * may be a bug. */ if (blessed(w, w1)) goto out; #endif /* Bail if this violation is known */ if (w_rmatrix[w1->w_index][w->w_index] & WITNESS_REVERSAL) goto out; /* Record this as a violation */ w_rmatrix[w1->w_index][w->w_index] |= WITNESS_REVERSAL; w_rmatrix[w->w_index][w1->w_index] |= WITNESS_REVERSAL; w->w_reversed = w1->w_reversed = 1; witness_increment_graph_generation(); mtx_unlock_spin(&w_mtx); /* * Ok, yell about it. */ if (((lock->lo_flags & LO_SLEEPABLE) != 0 && (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) printf( "lock order reversal: (sleepable after non-sleepable)\n"); else if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 && lock == &Giant.lock_object) printf( "lock order reversal: (Giant after non-sleepable)\n"); else printf("lock order reversal:\n"); /* * Try to locate an earlier lock with * witness w in our list. */ do { lock2 = &lle->ll_children[i]; MPASS(lock2->li_lock != NULL); if (lock2->li_lock->lo_witness == w) break; if (i == 0 && lle->ll_next != NULL) { lle = lle->ll_next; i = lle->ll_count - 1; MPASS(i >= 0 && i < LOCK_NCHILDREN); } else i--; } while (i >= 0); if (i < 0) { printf(" 1st %p %s (%s) @ %s:%d\n", lock1->li_lock, lock1->li_lock->lo_name, w1->w_name, fixup_filename(lock1->li_file), lock1->li_line); printf(" 2nd %p %s (%s) @ %s:%d\n", lock, lock->lo_name, w->w_name, fixup_filename(file), line); } else { printf(" 1st %p %s (%s) @ %s:%d\n", lock2->li_lock, lock2->li_lock->lo_name, lock2->li_lock->lo_witness->w_name, fixup_filename(lock2->li_file), lock2->li_line); printf(" 2nd %p %s (%s) @ %s:%d\n", lock1->li_lock, lock1->li_lock->lo_name, w1->w_name, fixup_filename(lock1->li_file), lock1->li_line); printf(" 3rd %p %s (%s) @ %s:%d\n", lock, lock->lo_name, w->w_name, fixup_filename(file), line); } witness_debugger(1); return; } } /* * If requested, build a new lock order. However, don't build a new * relationship between a sleepable lock and Giant if it is in the * wrong direction. The correct lock order is that sleepable locks * always come before Giant. */ if (flags & LOP_NEWORDER && !(plock->li_lock == &Giant.lock_object && (lock->lo_flags & LO_SLEEPABLE) != 0)) { CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, w->w_name, plock->li_lock->lo_witness->w_name); itismychild(plock->li_lock->lo_witness, w); } out: mtx_unlock_spin(&w_mtx); } void witness_lock(struct lock_object *lock, int flags, const char *file, int line) { struct lock_list_entry **lock_list, *lle; struct lock_instance *instance; struct witness *w; struct thread *td; if (witness_cold || witness_watch == -1 || lock->lo_witness == NULL || panicstr != NULL) return; w = lock->lo_witness; td = curthread; /* Determine lock list for this lock. */ if (LOCK_CLASS(lock)->lc_flags & LC_SLEEPLOCK) lock_list = &td->td_sleeplocks; else lock_list = PCPU_PTR(spinlocks); /* Check to see if we are recursing on a lock we already own. */ instance = find_instance(*lock_list, lock); if (instance != NULL) { instance->li_flags++; CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, td->td_proc->p_pid, lock->lo_name, instance->li_flags & LI_RECURSEMASK); instance->li_file = file; instance->li_line = line; return; } /* Update per-witness last file and line acquire. */ w->w_file = file; w->w_line = line; /* Find the next open lock instance in the list and fill it. */ lle = *lock_list; if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { lle = witness_lock_list_get(); if (lle == NULL) return; lle->ll_next = *lock_list; CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, td->td_proc->p_pid, lle); *lock_list = lle; } instance = &lle->ll_children[lle->ll_count++]; instance->li_lock = lock; instance->li_line = line; instance->li_file = file; if ((flags & LOP_EXCLUSIVE) != 0) instance->li_flags = LI_EXCLUSIVE; else instance->li_flags = 0; CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); } void witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) { struct lock_instance *instance; struct lock_class *class; KASSERT(witness_cold == 0, ("%s: witness_cold", __func__)); if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL) return; class = LOCK_CLASS(lock); if (witness_watch) { if ((lock->lo_flags & LO_UPGRADABLE) == 0) panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", class->lc_name, lock->lo_name, fixup_filename(file), line); if ((class->lc_flags & LC_SLEEPLOCK) == 0) panic("upgrade of non-sleep lock (%s) %s @ %s:%d", class->lc_name, lock->lo_name, fixup_filename(file), line); } instance = find_instance(curthread->td_sleeplocks, lock); if (instance == NULL) panic("upgrade of unlocked lock (%s) %s @ %s:%d", class->lc_name, lock->lo_name, fixup_filename(file), line); if (witness_watch) { if ((instance->li_flags & LI_EXCLUSIVE) != 0) panic("upgrade of exclusive lock (%s) %s @ %s:%d", class->lc_name, lock->lo_name, fixup_filename(file), line); if ((instance->li_flags & LI_RECURSEMASK) != 0) panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", class->lc_name, lock->lo_name, instance->li_flags & LI_RECURSEMASK, fixup_filename(file), line); } instance->li_flags |= LI_EXCLUSIVE; } void witness_downgrade(struct lock_object *lock, int flags, const char *file, int line) { struct lock_instance *instance; struct lock_class *class; KASSERT(witness_cold == 0, ("%s: witness_cold", __func__)); if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL) return; class = LOCK_CLASS(lock); if (witness_watch) { if ((lock->lo_flags & LO_UPGRADABLE) == 0) panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", class->lc_name, lock->lo_name, fixup_filename(file), line); if ((class->lc_flags & LC_SLEEPLOCK) == 0) panic("downgrade of non-sleep lock (%s) %s @ %s:%d", class->lc_name, lock->lo_name, fixup_filename(file), line); } instance = find_instance(curthread->td_sleeplocks, lock); if (instance == NULL) panic("downgrade of unlocked lock (%s) %s @ %s:%d", class->lc_name, lock->lo_name, fixup_filename(file), line); if (witness_watch) { if ((instance->li_flags & LI_EXCLUSIVE) == 0) panic("downgrade of shared lock (%s) %s @ %s:%d", class->lc_name, lock->lo_name, fixup_filename(file), line); if ((instance->li_flags & LI_RECURSEMASK) != 0) panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", class->lc_name, lock->lo_name, instance->li_flags & LI_RECURSEMASK, fixup_filename(file), line); } instance->li_flags &= ~LI_EXCLUSIVE; } void witness_unlock(struct lock_object *lock, int flags, const char *file, int line) { struct lock_list_entry **lock_list, *lle; struct lock_instance *instance; struct lock_class *class; struct thread *td; register_t s; int i, j; if (witness_cold || lock->lo_witness == NULL || panicstr != NULL) return; td = curthread; class = LOCK_CLASS(lock); /* Find lock instance associated with this lock. */ if (class->lc_flags & LC_SLEEPLOCK) lock_list = &td->td_sleeplocks; else lock_list = PCPU_PTR(spinlocks); lle = *lock_list; for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) for (i = 0; i < (*lock_list)->ll_count; i++) { instance = &(*lock_list)->ll_children[i]; if (instance->li_lock == lock) goto found; } /* * When disabling WITNESS through witness_watch we could end up in * having registered locks in the td_sleeplocks queue. * We have to make sure we flush these queues, so just search for * eventual register locks and remove them. */ if (witness_watch > 0) panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, fixup_filename(file), line); else return; found: /* First, check for shared/exclusive mismatches. */ if ((instance->li_flags & LI_EXCLUSIVE) != 0 && witness_watch > 0 && (flags & LOP_EXCLUSIVE) == 0) { printf("shared unlock of (%s) %s @ %s:%d\n", class->lc_name, lock->lo_name, fixup_filename(file), line); printf("while exclusively locked from %s:%d\n", fixup_filename(instance->li_file), instance->li_line); panic("excl->ushare"); } if ((instance->li_flags & LI_EXCLUSIVE) == 0 && witness_watch > 0 && (flags & LOP_EXCLUSIVE) != 0) { printf("exclusive unlock of (%s) %s @ %s:%d\n", class->lc_name, lock->lo_name, fixup_filename(file), line); printf("while share locked from %s:%d\n", fixup_filename(instance->li_file), instance->li_line); panic("share->uexcl"); } /* If we are recursed, unrecurse. */ if ((instance->li_flags & LI_RECURSEMASK) > 0) { CTR4(KTR_WITNESS, "%s: pid %d unrecursed on %s r=%d", __func__, td->td_proc->p_pid, instance->li_lock->lo_name, instance->li_flags); instance->li_flags--; return; } /* The lock is now being dropped, check for NORELEASE flag */ if ((instance->li_flags & LI_NORELEASE) != 0 && witness_watch > 0) { printf("forbidden unlock of (%s) %s @ %s:%d\n", class->lc_name, lock->lo_name, fixup_filename(file), line); panic("lock marked norelease"); } /* Otherwise, remove this item from the list. */ s = intr_disable(); CTR4(KTR_WITNESS, "%s: pid %d removed %s from lle[%d]", __func__, td->td_proc->p_pid, instance->li_lock->lo_name, (*lock_list)->ll_count - 1); for (j = i; j < (*lock_list)->ll_count - 1; j++) (*lock_list)->ll_children[j] = (*lock_list)->ll_children[j + 1]; (*lock_list)->ll_count--; intr_restore(s); /* * In order to reduce contention on w_mtx, we want to keep always an * head object into lists so that frequent allocation from the * free witness pool (and subsequent locking) is avoided. * In order to maintain the current code simple, when the head * object is totally unloaded it means also that we do not have * further objects in the list, so the list ownership needs to be * hand over to another object if the current head needs to be freed. */ if ((*lock_list)->ll_count == 0) { if (*lock_list == lle) { if (lle->ll_next == NULL) return; } else lle = *lock_list; *lock_list = lle->ll_next; CTR3(KTR_WITNESS, "%s: pid %d removed lle %p", __func__, td->td_proc->p_pid, lle); witness_lock_list_free(lle); } } void witness_thread_exit(struct thread *td) { struct lock_list_entry *lle; int i, n; lle = td->td_sleeplocks; if (lle == NULL || panicstr != NULL) return; if (lle->ll_count != 0) { for (n = 0; lle != NULL; lle = lle->ll_next) for (i = lle->ll_count - 1; i >= 0; i--) { if (n == 0) printf("Thread %p exiting with the following locks held:\n", td); n++; witness_list_lock(&lle->ll_children[i], printf); } panic("Thread %p cannot exit while holding sleeplocks\n", td); } witness_lock_list_free(lle); } /* * Warn if any locks other than 'lock' are held. Flags can be passed in to * exempt Giant and sleepable locks from the checks as well. If any * non-exempt locks are held, then a supplied message is printed to the * console along with a list of the offending locks. If indicated in the * flags then a failure results in a panic as well. */ int witness_warn(int flags, struct lock_object *lock, const char *fmt, ...) { struct lock_list_entry *lock_list, *lle; struct lock_instance *lock1; struct thread *td; va_list ap; int i, n; if (witness_cold || witness_watch < 1 || panicstr != NULL) return (0); n = 0; td = curthread; for (lle = td->td_sleeplocks; lle != NULL; lle = lle->ll_next) for (i = lle->ll_count - 1; i >= 0; i--) { lock1 = &lle->ll_children[i]; if (lock1->li_lock == lock) continue; if (flags & WARN_GIANTOK && lock1->li_lock == &Giant.lock_object) continue; if (flags & WARN_SLEEPOK && (lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) continue; if (n == 0) { va_start(ap, fmt); vprintf(fmt, ap); va_end(ap); printf(" with the following"); if (flags & WARN_SLEEPOK) printf(" non-sleepable"); printf(" locks held:\n"); } n++; witness_list_lock(lock1, printf); } /* * Pin the thread in order to avoid problems with thread migration. * Once that all verifies are passed about spinlocks ownership, * the thread is in a safe path and it can be unpinned. */ sched_pin(); lock_list = PCPU_GET(spinlocks); if (lock_list != NULL && lock_list->ll_count != 0) { sched_unpin(); /* * We should only have one spinlock and as long as * the flags cannot match for this locks class, * check if the first spinlock is the one curthread * should hold. */ lock1 = &lock_list->ll_children[lock_list->ll_count - 1]; if (lock_list->ll_count == 1 && lock_list->ll_next == NULL && lock1->li_lock == lock && n == 0) return (0); va_start(ap, fmt); vprintf(fmt, ap); va_end(ap); printf(" with the following"); if (flags & WARN_SLEEPOK) printf(" non-sleepable"); printf(" locks held:\n"); n += witness_list_locks(&lock_list, printf); } else sched_unpin(); if (flags & WARN_PANIC && n) panic("%s", __func__); else witness_debugger(n); return (n); } const char * witness_file(struct lock_object *lock) { struct witness *w; if (witness_cold || witness_watch < 1 || lock->lo_witness == NULL) return ("?"); w = lock->lo_witness; return (w->w_file); } int witness_line(struct lock_object *lock) { struct witness *w; if (witness_cold || witness_watch < 1 || lock->lo_witness == NULL) return (0); w = lock->lo_witness; return (w->w_line); } static struct witness * enroll(const char *description, struct lock_class *lock_class) { struct witness *w; struct witness_list *typelist; MPASS(description != NULL); if (witness_watch == -1 || panicstr != NULL) return (NULL); if ((lock_class->lc_flags & LC_SPINLOCK)) { if (witness_skipspin) return (NULL); else typelist = &w_spin; } else if ((lock_class->lc_flags & LC_SLEEPLOCK)) typelist = &w_sleep; else panic("lock class %s is not sleep or spin", lock_class->lc_name); mtx_lock_spin(&w_mtx); w = witness_hash_get(description); if (w) goto found; if ((w = witness_get()) == NULL) return (NULL); MPASS(strlen(description) < MAX_W_NAME); strcpy(w->w_name, description); w->w_class = lock_class; w->w_refcount = 1; STAILQ_INSERT_HEAD(&w_all, w, w_list); if (lock_class->lc_flags & LC_SPINLOCK) { STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); w_spin_cnt++; } else if (lock_class->lc_flags & LC_SLEEPLOCK) { STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); w_sleep_cnt++; } /* Insert new witness into the hash */ witness_hash_put(w); witness_increment_graph_generation(); mtx_unlock_spin(&w_mtx); return (w); found: w->w_refcount++; mtx_unlock_spin(&w_mtx); if (lock_class != w->w_class) panic( "lock (%s) %s does not match earlier (%s) lock", description, lock_class->lc_name, w->w_class->lc_name); return (w); } static void depart(struct witness *w) { struct witness_list *list; MPASS(w->w_refcount == 0); if (w->w_class->lc_flags & LC_SLEEPLOCK) { list = &w_sleep; w_sleep_cnt--; } else { list = &w_spin; w_spin_cnt--; } /* * Set file to NULL as it may point into a loadable module. */ w->w_file = NULL; w->w_line = 0; witness_increment_graph_generation(); } static void adopt(struct witness *parent, struct witness *child) { int pi, ci, i, j; if (witness_cold == 0) mtx_assert(&w_mtx, MA_OWNED); /* If the relationship is already known, there's no work to be done. */ if (isitmychild(parent, child)) return; /* When the structure of the graph changes, bump up the generation. */ witness_increment_graph_generation(); /* * The hard part ... create the direct relationship, then propagate all * indirect relationships. */ pi = parent->w_index; ci = child->w_index; WITNESS_INDEX_ASSERT(pi); WITNESS_INDEX_ASSERT(ci); MPASS(pi != ci); w_rmatrix[pi][ci] |= WITNESS_PARENT; w_rmatrix[ci][pi] |= WITNESS_CHILD; /* * If parent was not already an ancestor of child, * then we increment the descendant and ancestor counters. */ if ((w_rmatrix[pi][ci] & WITNESS_ANCESTOR) == 0) { parent->w_num_descendants++; child->w_num_ancestors++; } /* * Find each ancestor of 'pi'. Note that 'pi' itself is counted as * an ancestor of 'pi' during this loop. */ for (i = 1; i <= w_max_used_index; i++) { if ((w_rmatrix[i][pi] & WITNESS_ANCESTOR_MASK) == 0 && (i != pi)) continue; /* Find each descendant of 'i' and mark it as a descendant. */ for (j = 1; j <= w_max_used_index; j++) { /* * Skip children that are already marked as * descendants of 'i'. */ if (w_rmatrix[i][j] & WITNESS_ANCESTOR_MASK) continue; /* * We are only interested in descendants of 'ci'. Note * that 'ci' itself is counted as a descendant of 'ci'. */ if ((w_rmatrix[ci][j] & WITNESS_ANCESTOR_MASK) == 0 && (j != ci)) continue; w_rmatrix[i][j] |= WITNESS_ANCESTOR; w_rmatrix[j][i] |= WITNESS_DESCENDANT; w_data[i].w_num_descendants++; w_data[j].w_num_ancestors++; /* * Make sure we aren't marking a node as both an * ancestor and descendant. We should have caught * this as a lock order reversal earlier. */ if ((w_rmatrix[i][j] & WITNESS_ANCESTOR_MASK) && (w_rmatrix[i][j] & WITNESS_DESCENDANT_MASK)) { printf("witness rmatrix paradox! [%d][%d]=%d " "both ancestor and descendant\n", i, j, w_rmatrix[i][j]); kdb_backtrace(); printf("Witness disabled.\n"); witness_watch = -1; } if ((w_rmatrix[j][i] & WITNESS_ANCESTOR_MASK) && (w_rmatrix[j][i] & WITNESS_DESCENDANT_MASK)) { printf("witness rmatrix paradox! [%d][%d]=%d " "both ancestor and descendant\n", j, i, w_rmatrix[j][i]); kdb_backtrace(); printf("Witness disabled.\n"); witness_watch = -1; } } } } static void itismychild(struct witness *parent, struct witness *child) { MPASS(child != NULL && parent != NULL); if (witness_cold == 0) mtx_assert(&w_mtx, MA_OWNED); if (!witness_lock_type_equal(parent, child)) { if (witness_cold == 0) mtx_unlock_spin(&w_mtx); panic("%s: parent \"%s\" (%s) and child \"%s\" (%s) are not " "the same lock type", __func__, parent->w_name, parent->w_class->lc_name, child->w_name, child->w_class->lc_name); } adopt(parent, child); } /* * Generic code for the isitmy*() functions. The rmask parameter is the * expected relationship of w1 to w2. */ static int _isitmyx(struct witness *w1, struct witness *w2, int rmask, const char *fname) { unsigned char r1, r2; int i1, i2; i1 = w1->w_index; i2 = w2->w_index; WITNESS_INDEX_ASSERT(i1); WITNESS_INDEX_ASSERT(i2); r1 = w_rmatrix[i1][i2] & WITNESS_RELATED_MASK; r2 = w_rmatrix[i2][i1] & WITNESS_RELATED_MASK; /* The flags on one better be the inverse of the flags on the other */ if (!((WITNESS_ATOD(r1) == r2 && WITNESS_DTOA(r2) == r1) || (WITNESS_DTOA(r1) == r2 && WITNESS_ATOD(r2) == r1))) { printf("%s: rmatrix mismatch between %s (index %d) and %s " "(index %d): w_rmatrix[%d][%d] == %hhx but " "w_rmatrix[%d][%d] == %hhx\n", fname, w1->w_name, i1, w2->w_name, i2, i1, i2, r1, i2, i1, r2); kdb_backtrace(); printf("Witness disabled.\n"); witness_watch = -1; } return (r1 & rmask); } /* * Checks if @child is a direct child of @parent. */ static int isitmychild(struct witness *parent, struct witness *child) { return (_isitmyx(parent, child, WITNESS_PARENT, __func__)); } /* * Checks if @descendant is a direct or inderect descendant of @ancestor. */ static int isitmydescendant(struct witness *ancestor, struct witness *descendant) { return (_isitmyx(ancestor, descendant, WITNESS_ANCESTOR_MASK, __func__)); } #ifdef BLESSING static int blessed(struct witness *w1, struct witness *w2) { int i; struct witness_blessed *b; for (i = 0; i < blessed_count; i++) { b = &blessed_list[i]; if (strcmp(w1->w_name, b->b_lock1) == 0) { if (strcmp(w2->w_name, b->b_lock2) == 0) return (1); continue; } if (strcmp(w1->w_name, b->b_lock2) == 0) if (strcmp(w2->w_name, b->b_lock1) == 0) return (1); } return (0); } #endif static struct witness * witness_get(void) { struct witness *w; int index; if (witness_cold == 0) mtx_assert(&w_mtx, MA_OWNED); if (witness_watch == -1) { mtx_unlock_spin(&w_mtx); return (NULL); } if (STAILQ_EMPTY(&w_free)) { witness_watch = -1; mtx_unlock_spin(&w_mtx); printf("WITNESS: unable to allocate a new witness object\n"); return (NULL); } w = STAILQ_FIRST(&w_free); STAILQ_REMOVE_HEAD(&w_free, w_list); w_free_cnt--; index = w->w_index; MPASS(index > 0 && index == w_max_used_index+1 && index < WITNESS_COUNT); bzero(w, sizeof(*w)); w->w_index = index; if (index > w_max_used_index) w_max_used_index = index; return (w); } static void witness_free(struct witness *w) { STAILQ_INSERT_HEAD(&w_free, w, w_list); w_free_cnt++; } static struct lock_list_entry * witness_lock_list_get(void) { struct lock_list_entry *lle; if (witness_watch == -1) return (NULL); mtx_lock_spin(&w_mtx); lle = w_lock_list_free; if (lle == NULL) { witness_watch = -1; mtx_unlock_spin(&w_mtx); printf("%s: witness exhausted\n", __func__); return (NULL); } w_lock_list_free = lle->ll_next; mtx_unlock_spin(&w_mtx); bzero(lle, sizeof(*lle)); return (lle); } static void witness_lock_list_free(struct lock_list_entry *lle) { mtx_lock_spin(&w_mtx); lle->ll_next = w_lock_list_free; w_lock_list_free = lle; mtx_unlock_spin(&w_mtx); } static struct lock_instance * find_instance(struct lock_list_entry *list, const struct lock_object *lock) { struct lock_list_entry *lle; struct lock_instance *instance; int i; for (lle = list; lle != NULL; lle = lle->ll_next) for (i = lle->ll_count - 1; i >= 0; i--) { instance = &lle->ll_children[i]; if (instance->li_lock == lock) return (instance); } return (NULL); } static void witness_list_lock(struct lock_instance *instance, int (*prnt)(const char *fmt, ...)) { struct lock_object *lock; lock = instance->li_lock; prnt("%s %s %s", (instance->li_flags & LI_EXCLUSIVE) != 0 ? "exclusive" : "shared", LOCK_CLASS(lock)->lc_name, lock->lo_name); if (lock->lo_witness->w_name != lock->lo_name) prnt(" (%s)", lock->lo_witness->w_name); prnt(" r = %d (%p) locked @ %s:%d\n", instance->li_flags & LI_RECURSEMASK, lock, fixup_filename(instance->li_file), instance->li_line); } #ifdef DDB static int witness_thread_has_locks(struct thread *td) { if (td->td_sleeplocks == NULL) return (0); return (td->td_sleeplocks->ll_count != 0); } static int witness_proc_has_locks(struct proc *p) { struct thread *td; FOREACH_THREAD_IN_PROC(p, td) { if (witness_thread_has_locks(td)) return (1); } return (0); } #endif int witness_list_locks(struct lock_list_entry **lock_list, int (*prnt)(const char *fmt, ...)) { struct lock_list_entry *lle; int i, nheld; nheld = 0; for (lle = *lock_list; lle != NULL; lle = lle->ll_next) for (i = lle->ll_count - 1; i >= 0; i--) { witness_list_lock(&lle->ll_children[i], prnt); nheld++; } return (nheld); } /* * This is a bit risky at best. We call this function when we have timed * out acquiring a spin lock, and we assume that the other CPU is stuck * with this lock held. So, we go groveling around in the other CPU's * per-cpu data to try to find the lock instance for this spin lock to * see when it was last acquired. */ void witness_display_spinlock(struct lock_object *lock, struct thread *owner, int (*prnt)(const char *fmt, ...)) { struct lock_instance *instance; struct pcpu *pc; if (owner->td_critnest == 0 || owner->td_oncpu == NOCPU) return; pc = pcpu_find(owner->td_oncpu); instance = find_instance(pc->pc_spinlocks, lock); if (instance != NULL) witness_list_lock(instance, prnt); } void witness_save(struct lock_object *lock, const char **filep, int *linep) { struct lock_list_entry *lock_list; struct lock_instance *instance; struct lock_class *class; + /* + * This function is used independently in locking code to deal with + * Giant, SCHEDULER_STOPPED() check can be removed here after Giant + * is gone. + */ + if (SCHEDULER_STOPPED()) + return; KASSERT(witness_cold == 0, ("%s: witness_cold", __func__)); if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL) return; class = LOCK_CLASS(lock); if (class->lc_flags & LC_SLEEPLOCK) lock_list = curthread->td_sleeplocks; else { if (witness_skipspin) return; lock_list = PCPU_GET(spinlocks); } instance = find_instance(lock_list, lock); if (instance == NULL) panic("%s: lock (%s) %s not locked", __func__, class->lc_name, lock->lo_name); *filep = instance->li_file; *linep = instance->li_line; } void witness_restore(struct lock_object *lock, const char *file, int line) { struct lock_list_entry *lock_list; struct lock_instance *instance; struct lock_class *class; + /* + * This function is used independently in locking code to deal with + * Giant, SCHEDULER_STOPPED() check can be removed here after Giant + * is gone. + */ + if (SCHEDULER_STOPPED()) + return; KASSERT(witness_cold == 0, ("%s: witness_cold", __func__)); if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL) return; class = LOCK_CLASS(lock); if (class->lc_flags & LC_SLEEPLOCK) lock_list = curthread->td_sleeplocks; else { if (witness_skipspin) return; lock_list = PCPU_GET(spinlocks); } instance = find_instance(lock_list, lock); if (instance == NULL) panic("%s: lock (%s) %s not locked", __func__, class->lc_name, lock->lo_name); lock->lo_witness->w_file = file; lock->lo_witness->w_line = line; instance->li_file = file; instance->li_line = line; } void witness_assert(const struct lock_object *lock, int flags, const char *file, int line) { #ifdef INVARIANT_SUPPORT struct lock_instance *instance; struct lock_class *class; if (lock->lo_witness == NULL || witness_watch < 1 || panicstr != NULL) return; class = LOCK_CLASS(lock); if ((class->lc_flags & LC_SLEEPLOCK) != 0) instance = find_instance(curthread->td_sleeplocks, lock); else if ((class->lc_flags & LC_SPINLOCK) != 0) instance = find_instance(PCPU_GET(spinlocks), lock); else { panic("Lock (%s) %s is not sleep or spin!", class->lc_name, lock->lo_name); } switch (flags) { case LA_UNLOCKED: if (instance != NULL) panic("Lock (%s) %s locked @ %s:%d.", class->lc_name, lock->lo_name, fixup_filename(file), line); break; case LA_LOCKED: case LA_LOCKED | LA_RECURSED: case LA_LOCKED | LA_NOTRECURSED: case LA_SLOCKED: case LA_SLOCKED | LA_RECURSED: case LA_SLOCKED | LA_NOTRECURSED: case LA_XLOCKED: case LA_XLOCKED | LA_RECURSED: case LA_XLOCKED | LA_NOTRECURSED: if (instance == NULL) { panic("Lock (%s) %s not locked @ %s:%d.", class->lc_name, lock->lo_name, fixup_filename(file), line); break; } if ((flags & LA_XLOCKED) != 0 && (instance->li_flags & LI_EXCLUSIVE) == 0) panic("Lock (%s) %s not exclusively locked @ %s:%d.", class->lc_name, lock->lo_name, fixup_filename(file), line); if ((flags & LA_SLOCKED) != 0 && (instance->li_flags & LI_EXCLUSIVE) != 0) panic("Lock (%s) %s exclusively locked @ %s:%d.", class->lc_name, lock->lo_name, fixup_filename(file), line); if ((flags & LA_RECURSED) != 0 && (instance->li_flags & LI_RECURSEMASK) == 0) panic("Lock (%s) %s not recursed @ %s:%d.", class->lc_name, lock->lo_name, fixup_filename(file), line); if ((flags & LA_NOTRECURSED) != 0 && (instance->li_flags & LI_RECURSEMASK) != 0) panic("Lock (%s) %s recursed @ %s:%d.", class->lc_name, lock->lo_name, fixup_filename(file), line); break; default: panic("Invalid lock assertion at %s:%d.", fixup_filename(file), line); } #endif /* INVARIANT_SUPPORT */ } static void witness_setflag(struct lock_object *lock, int flag, int set) { struct lock_list_entry *lock_list; struct lock_instance *instance; struct lock_class *class; if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL) return; class = LOCK_CLASS(lock); if (class->lc_flags & LC_SLEEPLOCK) lock_list = curthread->td_sleeplocks; else { if (witness_skipspin) return; lock_list = PCPU_GET(spinlocks); } instance = find_instance(lock_list, lock); if (instance == NULL) panic("%s: lock (%s) %s not locked", __func__, class->lc_name, lock->lo_name); if (set) instance->li_flags |= flag; else instance->li_flags &= ~flag; } void witness_norelease(struct lock_object *lock) { witness_setflag(lock, LI_NORELEASE, 1); } void witness_releaseok(struct lock_object *lock) { witness_setflag(lock, LI_NORELEASE, 0); } #ifdef DDB static void witness_ddb_list(struct thread *td) { KASSERT(witness_cold == 0, ("%s: witness_cold", __func__)); KASSERT(kdb_active, ("%s: not in the debugger", __func__)); if (witness_watch < 1) return; witness_list_locks(&td->td_sleeplocks, db_printf); /* * We only handle spinlocks if td == curthread. This is somewhat broken * if td is currently executing on some other CPU and holds spin locks * as we won't display those locks. If we had a MI way of getting * the per-cpu data for a given cpu then we could use * td->td_oncpu to get the list of spinlocks for this thread * and "fix" this. * * That still wouldn't really fix this unless we locked the scheduler * lock or stopped the other CPU to make sure it wasn't changing the * list out from under us. It is probably best to just not try to * handle threads on other CPU's for now. */ if (td == curthread && PCPU_GET(spinlocks) != NULL) witness_list_locks(PCPU_PTR(spinlocks), db_printf); } DB_SHOW_COMMAND(locks, db_witness_list) { struct thread *td; if (have_addr) td = db_lookup_thread(addr, TRUE); else td = kdb_thread; witness_ddb_list(td); } DB_SHOW_ALL_COMMAND(locks, db_witness_list_all) { struct thread *td; struct proc *p; /* * It would be nice to list only threads and processes that actually * held sleep locks, but that information is currently not exported * by WITNESS. */ FOREACH_PROC_IN_SYSTEM(p) { if (!witness_proc_has_locks(p)) continue; FOREACH_THREAD_IN_PROC(p, td) { if (!witness_thread_has_locks(td)) continue; db_printf("Process %d (%s) thread %p (%d)\n", p->p_pid, p->p_comm, td, td->td_tid); witness_ddb_list(td); } } } DB_SHOW_ALIAS(alllocks, db_witness_list_all) DB_SHOW_COMMAND(witness, db_witness_display) { witness_ddb_display(db_printf); } #endif static int sysctl_debug_witness_badstacks(SYSCTL_HANDLER_ARGS) { struct witness_lock_order_data *data1, *data2, *tmp_data1, *tmp_data2; struct witness *tmp_w1, *tmp_w2, *w1, *w2; struct sbuf *sb; u_int w_rmatrix1, w_rmatrix2; int error, generation, i, j; tmp_data1 = NULL; tmp_data2 = NULL; tmp_w1 = NULL; tmp_w2 = NULL; if (witness_watch < 1) { error = SYSCTL_OUT(req, w_notrunning, sizeof(w_notrunning)); return (error); } if (witness_cold) { error = SYSCTL_OUT(req, w_stillcold, sizeof(w_stillcold)); return (error); } error = 0; sb = sbuf_new(NULL, NULL, BADSTACK_SBUF_SIZE, SBUF_AUTOEXTEND); if (sb == NULL) return (ENOMEM); /* Allocate and init temporary storage space. */ tmp_w1 = malloc(sizeof(struct witness), M_TEMP, M_WAITOK | M_ZERO); tmp_w2 = malloc(sizeof(struct witness), M_TEMP, M_WAITOK | M_ZERO); tmp_data1 = malloc(sizeof(struct witness_lock_order_data), M_TEMP, M_WAITOK | M_ZERO); tmp_data2 = malloc(sizeof(struct witness_lock_order_data), M_TEMP, M_WAITOK | M_ZERO); stack_zero(&tmp_data1->wlod_stack); stack_zero(&tmp_data2->wlod_stack); restart: mtx_lock_spin(&w_mtx); generation = w_generation; mtx_unlock_spin(&w_mtx); sbuf_printf(sb, "Number of known direct relationships is %d\n", w_lohash.wloh_count); for (i = 1; i < w_max_used_index; i++) { mtx_lock_spin(&w_mtx); if (generation != w_generation) { mtx_unlock_spin(&w_mtx); /* The graph has changed, try again. */ req->oldidx = 0; sbuf_clear(sb); goto restart; } w1 = &w_data[i]; if (w1->w_reversed == 0) { mtx_unlock_spin(&w_mtx); continue; } /* Copy w1 locally so we can release the spin lock. */ *tmp_w1 = *w1; mtx_unlock_spin(&w_mtx); if (tmp_w1->w_reversed == 0) continue; for (j = 1; j < w_max_used_index; j++) { if ((w_rmatrix[i][j] & WITNESS_REVERSAL) == 0 || i > j) continue; mtx_lock_spin(&w_mtx); if (generation != w_generation) { mtx_unlock_spin(&w_mtx); /* The graph has changed, try again. */ req->oldidx = 0; sbuf_clear(sb); goto restart; } w2 = &w_data[j]; data1 = witness_lock_order_get(w1, w2); data2 = witness_lock_order_get(w2, w1); /* * Copy information locally so we can release the * spin lock. */ *tmp_w2 = *w2; w_rmatrix1 = (unsigned int)w_rmatrix[i][j]; w_rmatrix2 = (unsigned int)w_rmatrix[j][i]; if (data1) { stack_zero(&tmp_data1->wlod_stack); stack_copy(&data1->wlod_stack, &tmp_data1->wlod_stack); } if (data2 && data2 != data1) { stack_zero(&tmp_data2->wlod_stack); stack_copy(&data2->wlod_stack, &tmp_data2->wlod_stack); } mtx_unlock_spin(&w_mtx); sbuf_printf(sb, "\nLock order reversal between \"%s\"(%s) and \"%s\"(%s)!\n", tmp_w1->w_name, tmp_w1->w_class->lc_name, tmp_w2->w_name, tmp_w2->w_class->lc_name); #if 0 sbuf_printf(sb, "w_rmatrix[%s][%s] == %x, w_rmatrix[%s][%s] == %x\n", tmp_w1->name, tmp_w2->w_name, w_rmatrix1, tmp_w2->name, tmp_w1->w_name, w_rmatrix2); #endif if (data1) { sbuf_printf(sb, "Lock order \"%s\"(%s) -> \"%s\"(%s) first seen at:\n", tmp_w1->w_name, tmp_w1->w_class->lc_name, tmp_w2->w_name, tmp_w2->w_class->lc_name); stack_sbuf_print(sb, &tmp_data1->wlod_stack); sbuf_printf(sb, "\n"); } if (data2 && data2 != data1) { sbuf_printf(sb, "Lock order \"%s\"(%s) -> \"%s\"(%s) first seen at:\n", tmp_w2->w_name, tmp_w2->w_class->lc_name, tmp_w1->w_name, tmp_w1->w_class->lc_name); stack_sbuf_print(sb, &tmp_data2->wlod_stack); sbuf_printf(sb, "\n"); } } } mtx_lock_spin(&w_mtx); if (generation != w_generation) { mtx_unlock_spin(&w_mtx); /* * The graph changed while we were printing stack data, * try again. */ req->oldidx = 0; sbuf_clear(sb); goto restart; } mtx_unlock_spin(&w_mtx); /* Free temporary storage space. */ free(tmp_data1, M_TEMP); free(tmp_data2, M_TEMP); free(tmp_w1, M_TEMP); free(tmp_w2, M_TEMP); sbuf_finish(sb); error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1); sbuf_delete(sb); return (error); } static int sysctl_debug_witness_fullgraph(SYSCTL_HANDLER_ARGS) { struct witness *w; struct sbuf *sb; int error; if (witness_watch < 1) { error = SYSCTL_OUT(req, w_notrunning, sizeof(w_notrunning)); return (error); } if (witness_cold) { error = SYSCTL_OUT(req, w_stillcold, sizeof(w_stillcold)); return (error); } error = 0; error = sysctl_wire_old_buffer(req, 0); if (error != 0) return (error); sb = sbuf_new_for_sysctl(NULL, NULL, FULLGRAPH_SBUF_SIZE, req); if (sb == NULL) return (ENOMEM); sbuf_printf(sb, "\n"); mtx_lock_spin(&w_mtx); STAILQ_FOREACH(w, &w_all, w_list) w->w_displayed = 0; STAILQ_FOREACH(w, &w_all, w_list) witness_add_fullgraph(sb, w); mtx_unlock_spin(&w_mtx); /* * Close the sbuf and return to userland. */ error = sbuf_finish(sb); sbuf_delete(sb); return (error); } static int sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS) { int error, value; value = witness_watch; error = sysctl_handle_int(oidp, &value, 0, req); if (error != 0 || req->newptr == NULL) return (error); if (value > 1 || value < -1 || (witness_watch == -1 && value != witness_watch)) return (EINVAL); witness_watch = value; return (0); } static void witness_add_fullgraph(struct sbuf *sb, struct witness *w) { int i; if (w->w_displayed != 0 || (w->w_file == NULL && w->w_line == 0)) return; w->w_displayed = 1; WITNESS_INDEX_ASSERT(w->w_index); for (i = 1; i <= w_max_used_index; i++) { if (w_rmatrix[w->w_index][i] & WITNESS_PARENT) { sbuf_printf(sb, "\"%s\",\"%s\"\n", w->w_name, w_data[i].w_name); witness_add_fullgraph(sb, &w_data[i]); } } } /* * A simple hash function. Takes a key pointer and a key size. If size == 0, * interprets the key as a string and reads until the null * terminator. Otherwise, reads the first size bytes. Returns an unsigned 32-bit * hash value computed from the key. */ static uint32_t witness_hash_djb2(const uint8_t *key, uint32_t size) { unsigned int hash = 5381; int i; /* hash = hash * 33 + key[i] */ if (size) for (i = 0; i < size; i++) hash = ((hash << 5) + hash) + (unsigned int)key[i]; else for (i = 0; key[i] != 0; i++) hash = ((hash << 5) + hash) + (unsigned int)key[i]; return (hash); } /* * Initializes the two witness hash tables. Called exactly once from * witness_initialize(). */ static void witness_init_hash_tables(void) { int i; MPASS(witness_cold); /* Initialize the hash tables. */ for (i = 0; i < WITNESS_HASH_SIZE; i++) w_hash.wh_array[i] = NULL; w_hash.wh_size = WITNESS_HASH_SIZE; w_hash.wh_count = 0; /* Initialize the lock order data hash. */ w_lofree = NULL; for (i = 0; i < WITNESS_LO_DATA_COUNT; i++) { memset(&w_lodata[i], 0, sizeof(w_lodata[i])); w_lodata[i].wlod_next = w_lofree; w_lofree = &w_lodata[i]; } w_lohash.wloh_size = WITNESS_LO_HASH_SIZE; w_lohash.wloh_count = 0; for (i = 0; i < WITNESS_LO_HASH_SIZE; i++) w_lohash.wloh_array[i] = NULL; } static struct witness * witness_hash_get(const char *key) { struct witness *w; uint32_t hash; MPASS(key != NULL); if (witness_cold == 0) mtx_assert(&w_mtx, MA_OWNED); hash = witness_hash_djb2(key, 0) % w_hash.wh_size; w = w_hash.wh_array[hash]; while (w != NULL) { if (strcmp(w->w_name, key) == 0) goto out; w = w->w_hash_next; } out: return (w); } static void witness_hash_put(struct witness *w) { uint32_t hash; MPASS(w != NULL); MPASS(w->w_name != NULL); if (witness_cold == 0) mtx_assert(&w_mtx, MA_OWNED); KASSERT(witness_hash_get(w->w_name) == NULL, ("%s: trying to add a hash entry that already exists!", __func__)); KASSERT(w->w_hash_next == NULL, ("%s: w->w_hash_next != NULL", __func__)); hash = witness_hash_djb2(w->w_name, 0) % w_hash.wh_size; w->w_hash_next = w_hash.wh_array[hash]; w_hash.wh_array[hash] = w; w_hash.wh_count++; } static struct witness_lock_order_data * witness_lock_order_get(struct witness *parent, struct witness *child) { struct witness_lock_order_data *data = NULL; struct witness_lock_order_key key; unsigned int hash; MPASS(parent != NULL && child != NULL); key.from = parent->w_index; key.to = child->w_index; WITNESS_INDEX_ASSERT(key.from); WITNESS_INDEX_ASSERT(key.to); if ((w_rmatrix[parent->w_index][child->w_index] & WITNESS_LOCK_ORDER_KNOWN) == 0) goto out; hash = witness_hash_djb2((const char*)&key, sizeof(key)) % w_lohash.wloh_size; data = w_lohash.wloh_array[hash]; while (data != NULL) { if (witness_lock_order_key_equal(&data->wlod_key, &key)) break; data = data->wlod_next; } out: return (data); } /* * Verify that parent and child have a known relationship, are not the same, * and child is actually a child of parent. This is done without w_mtx * to avoid contention in the common case. */ static int witness_lock_order_check(struct witness *parent, struct witness *child) { if (parent != child && w_rmatrix[parent->w_index][child->w_index] & WITNESS_LOCK_ORDER_KNOWN && isitmychild(parent, child)) return (1); return (0); } static int witness_lock_order_add(struct witness *parent, struct witness *child) { struct witness_lock_order_data *data = NULL; struct witness_lock_order_key key; unsigned int hash; MPASS(parent != NULL && child != NULL); key.from = parent->w_index; key.to = child->w_index; WITNESS_INDEX_ASSERT(key.from); WITNESS_INDEX_ASSERT(key.to); if (w_rmatrix[parent->w_index][child->w_index] & WITNESS_LOCK_ORDER_KNOWN) return (1); hash = witness_hash_djb2((const char*)&key, sizeof(key)) % w_lohash.wloh_size; w_rmatrix[parent->w_index][child->w_index] |= WITNESS_LOCK_ORDER_KNOWN; data = w_lofree; if (data == NULL) return (0); w_lofree = data->wlod_next; data->wlod_next = w_lohash.wloh_array[hash]; data->wlod_key = key; w_lohash.wloh_array[hash] = data; w_lohash.wloh_count++; stack_zero(&data->wlod_stack); stack_save(&data->wlod_stack); return (1); } /* Call this whenver the structure of the witness graph changes. */ static void witness_increment_graph_generation(void) { if (witness_cold == 0) mtx_assert(&w_mtx, MA_OWNED); w_generation++; } #ifdef KDB static void _witness_debugger(int cond, const char *msg) { if (witness_trace && cond) kdb_backtrace(); if (witness_kdb && cond) kdb_enter(KDB_WHY_WITNESS, msg); } #endif Index: head/sys/sys/lockstat.h =================================================================== --- head/sys/sys/lockstat.h (revision 228423) +++ head/sys/sys/lockstat.h (revision 228424) @@ -1,220 +1,227 @@ /*- * Copyright (c) 2008-2009 Stacey Son * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ */ /* * DTrace lockstat provider definitions * */ #ifndef _SYS_LOCKSTAT_H #define _SYS_LOCKSTAT_H #ifdef _KERNEL /* * Spin Locks */ #define LS_MTX_SPIN_LOCK_ACQUIRE 0 #define LS_MTX_SPIN_UNLOCK_RELEASE 1 #define LS_MTX_SPIN_LOCK_SPIN 2 /* * Adaptive Locks */ #define LS_MTX_LOCK_ACQUIRE 3 #define LS_MTX_UNLOCK_RELEASE 4 #define LS_MTX_LOCK_SPIN 5 #define LS_MTX_LOCK_BLOCK 6 #define LS_MTX_TRYLOCK_ACQUIRE 7 /* * Reader/Writer Locks */ #define LS_RW_RLOCK_ACQUIRE 8 #define LS_RW_RUNLOCK_RELEASE 9 #define LS_RW_WLOCK_ACQUIRE 10 #define LS_RW_WUNLOCK_RELEASE 11 #define LS_RW_RLOCK_SPIN 12 #define LS_RW_RLOCK_BLOCK 13 #define LS_RW_WLOCK_SPIN 14 #define LS_RW_WLOCK_BLOCK 15 #define LS_RW_TRYUPGRADE_UPGRADE 16 #define LS_RW_DOWNGRADE_DOWNGRADE 17 /* * Shared/Exclusive Locks */ #define LS_SX_SLOCK_ACQUIRE 18 #define LS_SX_SUNLOCK_RELEASE 19 #define LS_SX_XLOCK_ACQUIRE 20 #define LS_SX_XUNLOCK_RELEASE 21 #define LS_SX_SLOCK_SPIN 22 #define LS_SX_SLOCK_BLOCK 23 #define LS_SX_XLOCK_SPIN 24 #define LS_SX_XLOCK_BLOCK 25 #define LS_SX_TRYUPGRADE_UPGRADE 26 #define LS_SX_DOWNGRADE_DOWNGRADE 27 /* * Thread Locks */ #define LS_THREAD_LOCK_SPIN 28 /* * Lockmanager Locks * According to locking(9) Lockmgr locks are "Largely deprecated" * so no support for these have been added in the lockstat provider. */ #define LS_NPROBES 29 #define LS_MTX_LOCK "mtx_lock" #define LS_MTX_UNLOCK "mtx_unlock" #define LS_MTX_SPIN_LOCK "mtx_lock_spin" #define LS_MTX_SPIN_UNLOCK "mtx_unlock_spin" #define LS_MTX_TRYLOCK "mtx_trylock" #define LS_RW_RLOCK "rw_rlock" #define LS_RW_WLOCK "rw_wlock" #define LS_RW_RUNLOCK "rw_runlock" #define LS_RW_WUNLOCK "rw_wunlock" #define LS_RW_TRYUPGRADE "rw_try_upgrade" #define LS_RW_DOWNGRADE "rw_downgrade" #define LS_SX_SLOCK "sx_slock" #define LS_SX_XLOCK "sx_xlock" #define LS_SX_SUNLOCK "sx_sunlock" #define LS_SX_XUNLOCK "sx_xunlock" #define LS_SX_TRYUPGRADE "sx_try_upgrade" #define LS_SX_DOWNGRADE "sx_downgrade" #define LS_THREAD_LOCK "thread_lock" #define LS_ACQUIRE "acquire" #define LS_RELEASE "release" #define LS_SPIN "spin" #define LS_BLOCK "block" #define LS_UPGRADE "upgrade" #define LS_DOWNGRADE "downgrade" #define LS_TYPE_ADAPTIVE "adaptive" #define LS_TYPE_SPIN "spin" #define LS_TYPE_THREAD "thread" #define LS_TYPE_RW "rw" #define LS_TYPE_SX "sx" #define LSA_ACQUIRE (LS_TYPE_ADAPTIVE "-" LS_ACQUIRE) #define LSA_RELEASE (LS_TYPE_ADAPTIVE "-" LS_RELEASE) #define LSA_SPIN (LS_TYPE_ADAPTIVE "-" LS_SPIN) #define LSA_BLOCK (LS_TYPE_ADAPTIVE "-" LS_BLOCK) #define LSS_ACQUIRE (LS_TYPE_SPIN "-" LS_ACQUIRE) #define LSS_RELEASE (LS_TYPE_SPIN "-" LS_RELEASE) #define LSS_SPIN (LS_TYPE_SPIN "-" LS_SPIN) #define LSR_ACQUIRE (LS_TYPE_RW "-" LS_ACQUIRE) #define LSR_RELEASE (LS_TYPE_RW "-" LS_RELEASE) #define LSR_BLOCK (LS_TYPE_RW "-" LS_BLOCK) #define LSR_SPIN (LS_TYPE_RW "-" LS_SPIN) #define LSR_UPGRADE (LS_TYPE_RW "-" LS_UPGRADE) #define LSR_DOWNGRADE (LS_TYPE_RW "-" LS_DOWNGRADE) #define LSX_ACQUIRE (LS_TYPE_SX "-" LS_ACQUIRE) #define LSX_RELEASE (LS_TYPE_SX "-" LS_RELEASE) #define LSX_BLOCK (LS_TYPE_SX "-" LS_BLOCK) #define LSX_SPIN (LS_TYPE_SX "-" LS_SPIN) #define LSX_UPGRADE (LS_TYPE_SX "-" LS_UPGRADE) #define LSX_DOWNGRADE (LS_TYPE_SX "-" LS_DOWNGRADE) #define LST_SPIN (LS_TYPE_THREAD "-" LS_SPIN) /* * The following must match the type definition of dtrace_probe. It is * defined this way to avoid having to rely on CDDL code. */ extern uint32_t lockstat_probemap[LS_NPROBES]; typedef void (*lockstat_probe_func_t)(uint32_t, uintptr_t arg0, uintptr_t arg1, uintptr_t arg2, uintptr_t arg3, uintptr_t arg4); extern lockstat_probe_func_t lockstat_probe_func; extern uint64_t lockstat_nsecs(void); #ifdef KDTRACE_HOOKS /* * Macros to record lockstat probes. */ #define LOCKSTAT_RECORD4(probe, lp, arg1, arg2, arg3, arg4) do { \ uint32_t id; \ \ if ((id = lockstat_probemap[(probe)])) \ (*lockstat_probe_func)(id, (uintptr_t)(lp), (arg1), (arg2), \ (arg3), (arg4)); \ } while (0) #define LOCKSTAT_RECORD(probe, lp, arg1) \ LOCKSTAT_RECORD4(probe, lp, arg1, 0, 0, 0) #define LOCKSTAT_RECORD0(probe, lp) \ LOCKSTAT_RECORD4(probe, lp, 0, 0, 0, 0) #define LOCKSTAT_RECORD1(probe, lp, arg1) \ LOCKSTAT_RECORD4(probe, lp, arg1, 0, 0, 0) #define LOCKSTAT_RECORD2(probe, lp, arg1, arg2) \ LOCKSTAT_RECORD4(probe, lp, arg1, arg2, 0, 0) #define LOCKSTAT_RECORD3(probe, lp, arg1, arg2, arg3) \ LOCKSTAT_RECORD4(probe, lp, arg1, arg2, arg3, 0) #define LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(probe, lp, c, wt, f, l) do { \ uint32_t id; \ \ - lock_profile_obtain_lock_success(&(lp)->lock_object, c, wt, f, l); \ - if ((id = lockstat_probemap[(probe)])) \ - (*lockstat_probe_func)(id, (uintptr_t)(lp), 0, 0, 0, 0); \ + if (!SCHEDULER_STOPPED()) { \ + lock_profile_obtain_lock_success(&(lp)->lock_object, c, wt, \ + f, l); \ + if ((id = lockstat_probemap[(probe)])) \ + (*lockstat_probe_func)(id, (uintptr_t)(lp), 0, 0, \ + 0, 0); \ + } \ } while (0) #define LOCKSTAT_PROFILE_RELEASE_LOCK(probe, lp) do { \ uint32_t id; \ \ - lock_profile_release_lock(&(lp)->lock_object); \ - if ((id = lockstat_probemap[(probe)])) \ - (*lockstat_probe_func)(id, (uintptr_t)(lp), 0, 0, 0, 0); \ + if (!SCHEDULER_STOPPED()) { \ + lock_profile_release_lock(&(lp)->lock_object); \ + if ((id = lockstat_probemap[(probe)])) \ + (*lockstat_probe_func)(id, (uintptr_t)(lp), 0, 0, \ + 0, 0); \ + } \ } while (0) #else /* !KDTRACE_HOOKS */ #define LOCKSTAT_RECORD(probe, lp, arg1) #define LOCKSTAT_RECORD0(probe, lp) #define LOCKSTAT_RECORD1(probe, lp, arg1) #define LOCKSTAT_RECORD2(probe, lp, arg1, arg2) #define LOCKSTAT_RECORD3(probe, lp, arg1, arg2, arg3) #define LOCKSTAT_RECORD4(probe, lp, arg1, arg2, arg3, arg4) #define LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(probe, lp, c, wt, f, l) \ lock_profile_obtain_lock_success(&(lp)->lock_object, c, wt, f, l) #define LOCKSTAT_PROFILE_RELEASE_LOCK(probe, lp) \ lock_profile_release_lock(&(lp)->lock_object) #endif /* !KDTRACE_HOOKS */ #endif /* _KERNEL */ #endif /* _SYS_LOCKSTAT_H */ Index: head/sys/sys/mutex.h =================================================================== --- head/sys/sys/mutex.h (revision 228423) +++ head/sys/sys/mutex.h (revision 228424) @@ -1,433 +1,434 @@ /*- * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Berkeley Software Design Inc's name may not be used to endorse or * promote products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $ * $FreeBSD$ */ #ifndef _SYS_MUTEX_H_ #define _SYS_MUTEX_H_ #include #include #include #ifdef _KERNEL #include #include #include #include #include /* * Mutex types and options passed to mtx_init(). MTX_QUIET and MTX_DUPOK * can also be passed in. */ #define MTX_DEF 0x00000000 /* DEFAULT (sleep) lock */ #define MTX_SPIN 0x00000001 /* Spin lock (disables interrupts) */ #define MTX_RECURSE 0x00000004 /* Option: lock allowed to recurse */ #define MTX_NOWITNESS 0x00000008 /* Don't do any witness checking. */ #define MTX_NOPROFILE 0x00000020 /* Don't profile this lock */ /* * Option flags passed to certain lock/unlock routines, through the use * of corresponding mtx_{lock,unlock}_flags() interface macros. */ #define MTX_QUIET LOP_QUIET /* Don't log a mutex event */ #define MTX_DUPOK LOP_DUPOK /* Don't log a duplicate acquire */ /* * State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this, * with the exception of MTX_UNOWNED, applies to spin locks. */ #define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */ #define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */ #define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */ #define MTX_FLAGMASK (MTX_RECURSED | MTX_CONTESTED | MTX_UNOWNED) /* * Value stored in mutex->mtx_lock to denote a destroyed mutex. */ #define MTX_DESTROYED (MTX_CONTESTED | MTX_UNOWNED) /* * Prototypes * * NOTE: Functions prepended with `_' (underscore) are exported to other parts * of the kernel via macros, thus allowing us to use the cpp LOCK_FILE * and LOCK_LINE. These functions should not be called directly by any * code using the API. Their macros cover their functionality. * Functions with a `_' suffix are the entrypoint for the common * KPI covering both compat shims and fast path case. These can be * used by consumers willing to pass options, file and line * informations, in an option-independent way. * * [See below for descriptions] * */ void mtx_init(struct mtx *m, const char *name, const char *type, int opts); void mtx_destroy(struct mtx *m); void mtx_sysinit(void *arg); int mtx_trylock_flags_(struct mtx *m, int opts, const char *file, int line); void mutex_init(void); void _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, const char *file, int line); void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line); #ifdef SMP void _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts, const char *file, int line); #endif void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line); void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line); void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line); void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, int line); void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, int line); #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) void _mtx_assert(const struct mtx *m, int what, const char *file, int line); #endif void thread_lock_flags_(struct thread *, int, const char *, int); #define thread_lock(tdp) \ thread_lock_flags_((tdp), 0, __FILE__, __LINE__) #define thread_lock_flags(tdp, opt) \ thread_lock_flags_((tdp), (opt), __FILE__, __LINE__) #define thread_unlock(tdp) \ mtx_unlock_spin((tdp)->td_lock) #define mtx_recurse lock_object.lo_data /* Very simple operations on mtx_lock. */ /* Try to obtain mtx_lock once. */ #define _mtx_obtain_lock(mp, tid) \ atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid)) /* Try to release mtx_lock if it is unrecursed and uncontested. */ #define _mtx_release_lock(mp, tid) \ atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED) /* Release mtx_lock quickly, assuming we own it. */ #define _mtx_release_lock_quick(mp) \ atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED) /* * Full lock operations that are suitable to be inlined in non-debug * kernels. If the lock cannot be acquired or released trivially then * the work is deferred to another function. */ /* Lock a normal mutex. */ #define __mtx_lock(mp, tid, opts, file, line) do { \ uintptr_t _tid = (uintptr_t)(tid); \ \ if (!_mtx_obtain_lock((mp), _tid)) \ _mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \ else \ LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE, \ mp, 0, 0, (file), (line)); \ } while (0) /* * Lock a spin mutex. For spinlocks, we handle recursion inline (it * turns out that function calls can be significantly expensive on * some architectures). Since spin locks are not _too_ common, * inlining this code is not too big a deal. */ #ifdef SMP #define __mtx_lock_spin(mp, tid, opts, file, line) do { \ uintptr_t _tid = (uintptr_t)(tid); \ \ spinlock_enter(); \ if (!_mtx_obtain_lock((mp), _tid)) { \ if ((mp)->mtx_lock == _tid) \ (mp)->mtx_recurse++; \ else \ _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \ } else \ LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, \ mp, 0, 0, (file), (line)); \ } while (0) #else /* SMP */ #define __mtx_lock_spin(mp, tid, opts, file, line) do { \ uintptr_t _tid = (uintptr_t)(tid); \ \ spinlock_enter(); \ if ((mp)->mtx_lock == _tid) \ (mp)->mtx_recurse++; \ else { \ KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \ (mp)->mtx_lock = _tid; \ } \ } while (0) #endif /* SMP */ /* Unlock a normal mutex. */ #define __mtx_unlock(mp, tid, opts, file, line) do { \ uintptr_t _tid = (uintptr_t)(tid); \ \ if (!_mtx_release_lock((mp), _tid)) \ _mtx_unlock_sleep((mp), (opts), (file), (line)); \ } while (0) /* * Unlock a spin mutex. For spinlocks, we can handle everything * inline, as it's pretty simple and a function call would be too * expensive (at least on some architectures). Since spin locks are * not _too_ common, inlining this code is not too big a deal. * * Since we always perform a spinlock_enter() when attempting to acquire a * spin lock, we need to always perform a matching spinlock_exit() when * releasing a spin lock. This includes the recursion cases. */ #ifdef SMP #define __mtx_unlock_spin(mp) do { \ if (mtx_recursed((mp))) \ (mp)->mtx_recurse--; \ else { \ LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \ mp); \ _mtx_release_lock_quick((mp)); \ } \ spinlock_exit(); \ } while (0) #else /* SMP */ #define __mtx_unlock_spin(mp) do { \ if (mtx_recursed((mp))) \ (mp)->mtx_recurse--; \ else { \ LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_SPIN_UNLOCK_RELEASE, \ mp); \ (mp)->mtx_lock = MTX_UNOWNED; \ } \ spinlock_exit(); \ } while (0) #endif /* SMP */ /* * Exported lock manipulation interface. * * mtx_lock(m) locks MTX_DEF mutex `m' * * mtx_lock_spin(m) locks MTX_SPIN mutex `m' * * mtx_unlock(m) unlocks MTX_DEF mutex `m' * * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m' * * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m' * and passes option flags `opts' to the "hard" function, if required. * With these routines, it is possible to pass flags such as MTX_QUIET * to the appropriate lock manipulation routines. * * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if * it cannot. Rather, it returns 0 on failure and non-zero on success. * It does NOT handle recursion as we assume that if a caller is properly * using this part of the interface, he will know that the lock in question * is _not_ recursed. * * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts * relevant option flags `opts.' * * mtx_initialized(m) returns non-zero if the lock `m' has been initialized. * * mtx_owned(m) returns non-zero if the current thread owns the lock `m' * * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed. */ #define mtx_lock(m) mtx_lock_flags((m), 0) #define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0) #define mtx_trylock(m) mtx_trylock_flags((m), 0) #define mtx_unlock(m) mtx_unlock_flags((m), 0) #define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0) struct mtx_pool; struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts); void mtx_pool_destroy(struct mtx_pool **poolp); struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr); struct mtx *mtx_pool_alloc(struct mtx_pool *pool); #define mtx_pool_lock(pool, ptr) \ mtx_lock(mtx_pool_find((pool), (ptr))) #define mtx_pool_lock_spin(pool, ptr) \ mtx_lock_spin(mtx_pool_find((pool), (ptr))) #define mtx_pool_unlock(pool, ptr) \ mtx_unlock(mtx_pool_find((pool), (ptr))) #define mtx_pool_unlock_spin(pool, ptr) \ mtx_unlock_spin(mtx_pool_find((pool), (ptr))) /* * mtxpool_lockbuilder is a pool of sleep locks that is not witness * checked and should only be used for building higher level locks. * * mtxpool_sleep is a general purpose pool of sleep mutexes. */ extern struct mtx_pool *mtxpool_lockbuilder; extern struct mtx_pool *mtxpool_sleep; #ifndef LOCK_DEBUG #error LOCK_DEBUG not defined, include before #endif #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE) #define mtx_lock_flags_(m, opts, file, line) \ _mtx_lock_flags((m), (opts), (file), (line)) #define mtx_unlock_flags_(m, opts, file, line) \ _mtx_unlock_flags((m), (opts), (file), (line)) #define mtx_lock_spin_flags_(m, opts, file, line) \ _mtx_lock_spin_flags((m), (opts), (file), (line)) #define mtx_unlock_spin_flags_(m, opts, file, line) \ _mtx_unlock_spin_flags((m), (opts), (file), (line)) #else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */ #define mtx_lock_flags_(m, opts, file, line) \ __mtx_lock((m), curthread, (opts), (file), (line)) #define mtx_unlock_flags_(m, opts, file, line) \ __mtx_unlock((m), curthread, (opts), (file), (line)) #define mtx_lock_spin_flags_(m, opts, file, line) \ __mtx_lock_spin((m), curthread, (opts), (file), (line)) #define mtx_unlock_spin_flags_(m, opts, file, line) \ __mtx_unlock_spin((m)) #endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */ #ifdef INVARIANTS #define mtx_assert_(m, what, file, line) \ _mtx_assert((m), (what), (file), (line)) #define GIANT_REQUIRED mtx_assert_(&Giant, MA_OWNED, __FILE__, __LINE__) #else /* INVARIANTS */ #define mtx_assert_(m, what, file, line) (void)0 #define GIANT_REQUIRED #endif /* INVARIANTS */ #define mtx_lock_flags(m, opts) \ mtx_lock_flags_((m), (opts), LOCK_FILE, LOCK_LINE) #define mtx_unlock_flags(m, opts) \ mtx_unlock_flags_((m), (opts), LOCK_FILE, LOCK_LINE) #define mtx_lock_spin_flags(m, opts) \ mtx_lock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE) #define mtx_unlock_spin_flags(m, opts) \ mtx_unlock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE) #define mtx_trylock_flags(m, opts) \ mtx_trylock_flags_((m), (opts), LOCK_FILE, LOCK_LINE) #define mtx_assert(m, what) \ mtx_assert_((m), (what), __FILE__, __LINE__) #define mtx_sleep(chan, mtx, pri, wmesg, timo) \ _sleep((chan), &(mtx)->lock_object, (pri), (wmesg), (timo)) #define mtx_initialized(m) lock_initalized(&(m)->lock_object) #define mtx_owned(m) (((m)->mtx_lock & ~MTX_FLAGMASK) == (uintptr_t)curthread) #define mtx_recursed(m) ((m)->mtx_recurse != 0) #define mtx_name(m) ((m)->lock_object.lo_name) /* * Global locks. */ extern struct mtx Giant; extern struct mtx blocked_lock; /* * Giant lock manipulation and clean exit macros. * Used to replace return with an exit Giant and return. * * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT() * The #ifndef is to allow lint-like tools to redefine DROP_GIANT. */ #ifndef DROP_GIANT #define DROP_GIANT() \ do { \ int _giantcnt = 0; \ WITNESS_SAVE_DECL(Giant); \ \ if (mtx_owned(&Giant)) { \ WITNESS_SAVE(&Giant.lock_object, Giant); \ - for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \ + for (_giantcnt = 0; mtx_owned(&Giant) && \ + !SCHEDULER_STOPPED(); _giantcnt++) \ mtx_unlock(&Giant); \ } #define PICKUP_GIANT() \ PARTIAL_PICKUP_GIANT(); \ } while (0) #define PARTIAL_PICKUP_GIANT() \ mtx_assert(&Giant, MA_NOTOWNED); \ if (_giantcnt > 0) { \ while (_giantcnt--) \ mtx_lock(&Giant); \ WITNESS_RESTORE(&Giant.lock_object, Giant); \ } #endif #define UGAR(rval) do { \ int _val = (rval); \ mtx_unlock(&Giant); \ return (_val); \ } while (0) struct mtx_args { struct mtx *ma_mtx; const char *ma_desc; int ma_opts; }; #define MTX_SYSINIT(name, mtx, desc, opts) \ static struct mtx_args name##_args = { \ (mtx), \ (desc), \ (opts) \ }; \ SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ mtx_sysinit, &name##_args); \ SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ mtx_destroy, (mtx)) /* * The INVARIANTS-enabled mtx_assert() functionality. * * The constants need to be defined for INVARIANT_SUPPORT infrastructure * support as _mtx_assert() itself uses them and the latter implies that * _mtx_assert() must build. */ #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) #define MA_OWNED LA_XLOCKED #define MA_NOTOWNED LA_UNLOCKED #define MA_RECURSED LA_RECURSED #define MA_NOTRECURSED LA_NOTRECURSED #endif /* * Common lock type names. */ #define MTX_NETWORK_LOCK "network driver" #endif /* _KERNEL */ #endif /* _SYS_MUTEX_H_ */ Index: head/sys/sys/systm.h =================================================================== --- head/sys/sys/systm.h (revision 228423) +++ head/sys/sys/systm.h (revision 228424) @@ -1,406 +1,415 @@ /*- * Copyright (c) 1982, 1988, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)systm.h 8.7 (Berkeley) 3/29/95 * $FreeBSD$ */ #ifndef _SYS_SYSTM_H_ #define _SYS_SYSTM_H_ #include #include #include #include #include #include /* for people using printf mainly */ extern int cold; /* nonzero if we are doing a cold boot */ extern int rebooting; /* kern_reboot() has been called. */ +extern int stop_scheduler; /* only one thread runs after panic */ extern const char *panicstr; /* panic message */ extern char version[]; /* system version */ extern char copyright[]; /* system copyright */ extern int kstack_pages; /* number of kernel stack pages */ extern u_long pagesizes[]; /* supported page sizes */ extern long physmem; /* physical memory */ extern long realmem; /* 'real' memory */ extern char *rootdevnames[2]; /* names of possible root devices */ extern int boothowto; /* reboot flags, from console subsystem */ extern int bootverbose; /* nonzero to print verbose messages */ extern int maxusers; /* system tune hint */ extern int ngroups_max; /* max # of supplemental groups */ extern int vm_guest; /* Running as virtual machine guest? */ /* * Detected virtual machine guest types. The intention is to expand * and/or add to the VM_GUEST_VM type if specific VM functionality is * ever implemented (e.g. vendor-specific paravirtualization features). */ enum VM_GUEST { VM_GUEST_NO = 0, VM_GUEST_VM, VM_GUEST_XEN }; #ifdef INVARIANTS /* The option is always available */ #define KASSERT(exp,msg) do { \ if (__predict_false(!(exp))) \ panic msg; \ } while (0) #define VNASSERT(exp, vp, msg) do { \ if (__predict_false(!(exp))) { \ vn_printf(vp, "VNASSERT failed\n"); \ panic msg; \ } \ } while (0) #else #define KASSERT(exp,msg) do { \ } while (0) #define VNASSERT(exp, vp, msg) do { \ } while (0) #endif #ifndef CTASSERT /* Allow lint to override */ #define CTASSERT(x) _CTASSERT(x, __LINE__) #define _CTASSERT(x, y) __CTASSERT(x, y) #define __CTASSERT(x, y) typedef char __assert ## y[(x) ? 1 : -1] #endif /* * Assert that a pointer can be loaded from memory atomically. * * This assertion enforces stronger alignment than necessary. For example, * on some architectures, atomicity for unaligned loads will depend on * whether or not the load spans multiple cache lines. */ #define ASSERT_ATOMIC_LOAD_PTR(var, msg) \ KASSERT(sizeof(var) == sizeof(void *) && \ ((uintptr_t)&(var) & (sizeof(void *) - 1)) == 0, msg) + +/* + * If we have already panic'd and this is the thread that called + * panic(), then don't block on any mutexes but silently succeed. + * Otherwise, the kernel will deadlock since the scheduler isn't + * going to run the thread that holds any lock we need. + */ +#define SCHEDULER_STOPPED() __predict_false(stop_scheduler) /* * XXX the hints declarations are even more misplaced than most declarations * in this file, since they are needed in one file (per arch) and only used * in two files. * XXX most of these variables should be const. */ extern int osreldate; extern int envmode; extern int hintmode; /* 0 = off. 1 = config, 2 = fallback */ extern int dynamic_kenv; extern struct mtx kenv_lock; extern char *kern_envp; extern char static_env[]; extern char static_hints[]; /* by config for now */ extern char **kenvp; extern const void *zero_region; /* address space maps to a zeroed page */ /* * General function declarations. */ struct inpcb; struct lock_object; struct malloc_type; struct mtx; struct proc; struct socket; struct thread; struct tty; struct ucred; struct uio; struct _jmp_buf; struct trapframe; int setjmp(struct _jmp_buf *); void longjmp(struct _jmp_buf *, int) __dead2; int dumpstatus(vm_offset_t addr, off_t count); int nullop(void); int eopnotsupp(void); int ureadc(int, struct uio *); void hashdestroy(void *, struct malloc_type *, u_long); void *hashinit(int count, struct malloc_type *type, u_long *hashmask); void *hashinit_flags(int count, struct malloc_type *type, u_long *hashmask, int flags); #define HASH_NOWAIT 0x00000001 #define HASH_WAITOK 0x00000002 void *phashinit(int count, struct malloc_type *type, u_long *nentries); void g_waitidle(void); void panic(const char *, ...) __dead2 __printflike(1, 2); void cpu_boot(int); void cpu_flush_dcache(void *, size_t); void cpu_rootconf(void); void critical_enter(void); void critical_exit(void); void init_param1(void); void init_param2(long physpages); void init_static_kenv(char *, size_t); void tablefull(const char *); int kvprintf(char const *, void (*)(int, void*), void *, int, __va_list) __printflike(1, 0); void log(int, const char *, ...) __printflike(2, 3); void log_console(struct uio *); int printf(const char *, ...) __printflike(1, 2); int snprintf(char *, size_t, const char *, ...) __printflike(3, 4); int sprintf(char *buf, const char *, ...) __printflike(2, 3); int uprintf(const char *, ...) __printflike(1, 2); int vprintf(const char *, __va_list) __printflike(1, 0); int vsnprintf(char *, size_t, const char *, __va_list) __printflike(3, 0); int vsnrprintf(char *, size_t, int, const char *, __va_list) __printflike(4, 0); int vsprintf(char *buf, const char *, __va_list) __printflike(2, 0); int ttyprintf(struct tty *, const char *, ...) __printflike(2, 3); int sscanf(const char *, char const *, ...) __nonnull(1) __nonnull(2); int vsscanf(const char *, char const *, __va_list) __nonnull(1) __nonnull(2); long strtol(const char *, char **, int) __nonnull(1); u_long strtoul(const char *, char **, int) __nonnull(1); quad_t strtoq(const char *, char **, int) __nonnull(1); u_quad_t strtouq(const char *, char **, int) __nonnull(1); void tprintf(struct proc *p, int pri, const char *, ...) __printflike(3, 4); void hexdump(const void *ptr, int length, const char *hdr, int flags); #define HD_COLUMN_MASK 0xff #define HD_DELIM_MASK 0xff00 #define HD_OMIT_COUNT (1 << 16) #define HD_OMIT_HEX (1 << 17) #define HD_OMIT_CHARS (1 << 18) #define ovbcopy(f, t, l) bcopy((f), (t), (l)) void bcopy(const void *from, void *to, size_t len) __nonnull(1) __nonnull(2); void bzero(void *buf, size_t len) __nonnull(1); void *memcpy(void *to, const void *from, size_t len) __nonnull(1) __nonnull(2); void *memmove(void *dest, const void *src, size_t n) __nonnull(1) __nonnull(2); int copystr(const void * __restrict kfaddr, void * __restrict kdaddr, size_t len, size_t * __restrict lencopied) __nonnull(1) __nonnull(2); int copyinstr(const void * __restrict udaddr, void * __restrict kaddr, size_t len, size_t * __restrict lencopied) __nonnull(1) __nonnull(2); int copyin(const void * __restrict udaddr, void * __restrict kaddr, size_t len) __nonnull(1) __nonnull(2); int copyin_nofault(const void * __restrict udaddr, void * __restrict kaddr, size_t len) __nonnull(1) __nonnull(2); int copyout(const void * __restrict kaddr, void * __restrict udaddr, size_t len) __nonnull(1) __nonnull(2); int copyout_nofault(const void * __restrict kaddr, void * __restrict udaddr, size_t len) __nonnull(1) __nonnull(2); int fubyte(const void *base); long fuword(const void *base); int fuword16(void *base); int32_t fuword32(const void *base); int64_t fuword64(const void *base); int subyte(void *base, int byte); int suword(void *base, long word); int suword16(void *base, int word); int suword32(void *base, int32_t word); int suword64(void *base, int64_t word); uint32_t casuword32(volatile uint32_t *base, uint32_t oldval, uint32_t newval); u_long casuword(volatile u_long *p, u_long oldval, u_long newval); void realitexpire(void *); int sysbeep(int hertz, int period); void hardclock(int usermode, uintfptr_t pc); void hardclock_anycpu(int cnt, int usermode); void hardclock_cpu(int usermode); void hardclock_sync(int cpu); void softclock(void *); void statclock(int usermode); void profclock(int usermode, uintfptr_t pc); int hardclockintr(void); void startprofclock(struct proc *); void stopprofclock(struct proc *); void cpu_startprofclock(void); void cpu_stopprofclock(void); void cpu_idleclock(void); void cpu_activeclock(void); extern int cpu_can_deep_sleep; extern int cpu_disable_deep_sleep; int cr_cansee(struct ucred *u1, struct ucred *u2); int cr_canseesocket(struct ucred *cred, struct socket *so); int cr_canseeinpcb(struct ucred *cred, struct inpcb *inp); char *getenv(const char *name); void freeenv(char *env); int getenv_int(const char *name, int *data); int getenv_uint(const char *name, unsigned int *data); int getenv_long(const char *name, long *data); int getenv_ulong(const char *name, unsigned long *data); int getenv_string(const char *name, char *data, int size); int getenv_quad(const char *name, quad_t *data); int setenv(const char *name, const char *value); int unsetenv(const char *name); int testenv(const char *name); typedef uint64_t (cpu_tick_f)(void); void set_cputicker(cpu_tick_f *func, uint64_t freq, unsigned var); extern cpu_tick_f *cpu_ticks; uint64_t cpu_tickrate(void); uint64_t cputick2usec(uint64_t tick); #ifdef APM_FIXUP_CALLTODO struct timeval; void adjust_timeout_calltodo(struct timeval *time_change); #endif /* APM_FIXUP_CALLTODO */ #include /* Initialize the world */ void consinit(void); void cpu_initclocks(void); void cpu_initclocks_bsp(void); void cpu_initclocks_ap(void); void usrinfoinit(void); /* Finalize the world */ void kern_reboot(int) __dead2; void shutdown_nice(int); /* Timeouts */ typedef void timeout_t(void *); /* timeout function type */ #define CALLOUT_HANDLE_INITIALIZER(handle) \ { NULL } void callout_handle_init(struct callout_handle *); struct callout_handle timeout(timeout_t *, void *, int); void untimeout(timeout_t *, void *, struct callout_handle); caddr_t kern_timeout_callwheel_alloc(caddr_t v); void kern_timeout_callwheel_init(void); /* Stubs for obsolete functions that used to be for interrupt management */ static __inline void spl0(void) { return; } static __inline intrmask_t splbio(void) { return 0; } static __inline intrmask_t splcam(void) { return 0; } static __inline intrmask_t splclock(void) { return 0; } static __inline intrmask_t splhigh(void) { return 0; } static __inline intrmask_t splimp(void) { return 0; } static __inline intrmask_t splnet(void) { return 0; } static __inline intrmask_t splsoftcam(void) { return 0; } static __inline intrmask_t splsoftclock(void) { return 0; } static __inline intrmask_t splsofttty(void) { return 0; } static __inline intrmask_t splsoftvm(void) { return 0; } static __inline intrmask_t splsofttq(void) { return 0; } static __inline intrmask_t splstatclock(void) { return 0; } static __inline intrmask_t spltty(void) { return 0; } static __inline intrmask_t splvm(void) { return 0; } static __inline void splx(intrmask_t ipl __unused) { return; } /* * Common `proc' functions are declared here so that proc.h can be included * less often. */ int _sleep(void *chan, struct lock_object *lock, int pri, const char *wmesg, int timo) __nonnull(1); #define msleep(chan, mtx, pri, wmesg, timo) \ _sleep((chan), &(mtx)->lock_object, (pri), (wmesg), (timo)) int msleep_spin(void *chan, struct mtx *mtx, const char *wmesg, int timo) __nonnull(1); int pause(const char *wmesg, int timo); #define tsleep(chan, pri, wmesg, timo) \ _sleep((chan), NULL, (pri), (wmesg), (timo)) void wakeup(void *chan) __nonnull(1); void wakeup_one(void *chan) __nonnull(1); /* * Common `struct cdev *' stuff are declared here to avoid #include poisoning */ struct cdev; dev_t dev2udev(struct cdev *x); const char *devtoname(struct cdev *cdev); int poll_no_poll(int events); /* XXX: Should be void nanodelay(u_int nsec); */ void DELAY(int usec); /* Root mount holdback API */ struct root_hold_token; struct root_hold_token *root_mount_hold(const char *identifier); void root_mount_rel(struct root_hold_token *h); void root_mount_wait(void); int root_mounted(void); /* * Unit number allocation API. (kern/subr_unit.c) */ struct unrhdr; struct unrhdr *new_unrhdr(int low, int high, struct mtx *mutex); void delete_unrhdr(struct unrhdr *uh); void clean_unrhdr(struct unrhdr *uh); void clean_unrhdrl(struct unrhdr *uh); int alloc_unr(struct unrhdr *uh); int alloc_unr_specific(struct unrhdr *uh, u_int item); int alloc_unrl(struct unrhdr *uh); void free_unr(struct unrhdr *uh, u_int item); /* * Population count algorithm using SWAR approach * - "SIMD Within A Register". */ static __inline uint32_t bitcount32(uint32_t x) { x = (x & 0x55555555) + ((x & 0xaaaaaaaa) >> 1); x = (x & 0x33333333) + ((x & 0xcccccccc) >> 2); x = (x + (x >> 4)) & 0x0f0f0f0f; x = (x + (x >> 8)); x = (x + (x >> 16)) & 0x000000ff; return (x); } static __inline uint16_t bitcount16(uint32_t x) { x = (x & 0x5555) + ((x & 0xaaaa) >> 1); x = (x & 0x3333) + ((x & 0xcccc) >> 2); x = (x + (x >> 4)) & 0x0f0f; x = (x + (x >> 8)) & 0x00ff; return (x); } #endif /* !_SYS_SYSTM_H_ */