diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index 2017f824f6ad..2649d1d3a58f 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -1,3391 +1,3390 @@
 /*-
  * SPDX-License-Identifier: BSD-3-Clause
  *
  * Copyright (c) 1982, 1986, 1989, 1991, 1993
  *	The Regents of the University of California.  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 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_proc.c	8.7 (Berkeley) 2/14/95
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include "opt_ddb.h"
 #include "opt_ktrace.h"
 #include "opt_kstack_pages.h"
 #include "opt_stack.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bitstring.h>
 #include <sys/elf.h>
 #include <sys/eventhandler.h>
 #include <sys/exec.h>
 #include <sys/jail.h>
 #include <sys/kernel.h>
 #include <sys/limits.h>
 #include <sys/lock.h>
 #include <sys/loginclass.h>
 #include <sys/malloc.h>
 #include <sys/mman.h>
 #include <sys/mount.h>
 #include <sys/mutex.h>
 #include <sys/proc.h>
 #include <sys/ptrace.h>
 #include <sys/refcount.h>
 #include <sys/resourcevar.h>
 #include <sys/rwlock.h>
 #include <sys/sbuf.h>
 #include <sys/sysent.h>
 #include <sys/sched.h>
 #include <sys/smp.h>
 #include <sys/stack.h>
 #include <sys/stat.h>
 #include <sys/dtrace_bsd.h>
 #include <sys/sysctl.h>
 #include <sys/filedesc.h>
 #include <sys/tty.h>
 #include <sys/signalvar.h>
 #include <sys/sdt.h>
 #include <sys/sx.h>
 #include <sys/user.h>
 #include <sys/vnode.h>
 #include <sys/wait.h>
 #ifdef KTRACE
 #include <sys/ktrace.h>
 #endif
 
 #ifdef DDB
 #include <ddb/ddb.h>
 #endif
 
 #include <vm/vm.h>
 #include <vm/vm_param.h>
 #include <vm/vm_extern.h>
 #include <vm/pmap.h>
 #include <vm/vm_map.h>
 #include <vm/vm_object.h>
 #include <vm/vm_page.h>
 #include <vm/uma.h>
 
 #include <fs/devfs/devfs.h>
 
 #ifdef COMPAT_FREEBSD32
 #include <compat/freebsd32/freebsd32.h>
 #include <compat/freebsd32/freebsd32_util.h>
 #endif
 
 SDT_PROVIDER_DEFINE(proc);
 
 MALLOC_DEFINE(M_SESSION, "session", "session header");
 static MALLOC_DEFINE(M_PROC, "proc", "Proc structures");
 MALLOC_DEFINE(M_SUBPROC, "subproc", "Proc sub-structures");
 
 static void doenterpgrp(struct proc *, struct pgrp *);
 static void orphanpg(struct pgrp *pg);
 static void fill_kinfo_aggregate(struct proc *p, struct kinfo_proc *kp);
 static void fill_kinfo_proc_only(struct proc *p, struct kinfo_proc *kp);
 static void fill_kinfo_thread(struct thread *td, struct kinfo_proc *kp,
     int preferthread);
 static void pgdelete(struct pgrp *);
 static int pgrp_init(void *mem, int size, int flags);
 static int proc_ctor(void *mem, int size, void *arg, int flags);
 static void proc_dtor(void *mem, int size, void *arg);
 static int proc_init(void *mem, int size, int flags);
 static void proc_fini(void *mem, int size);
 static void pargs_free(struct pargs *pa);
 
 /*
  * Other process lists
  */
-struct pidhashhead *pidhashtbl;
+struct pidhashhead *pidhashtbl = NULL;
 struct sx *pidhashtbl_lock;
 u_long pidhash;
 u_long pidhashlock;
 struct pgrphashhead *pgrphashtbl;
 u_long pgrphash;
-struct proclist allproc;
+struct proclist allproc = LIST_HEAD_INITIALIZER(allproc);
 struct sx __exclusive_cache_line allproc_lock;
 struct sx __exclusive_cache_line proctree_lock;
 struct mtx __exclusive_cache_line ppeers_lock;
 struct mtx __exclusive_cache_line procid_lock;
 uma_zone_t proc_zone;
 uma_zone_t pgrp_zone;
 
 /*
  * The offset of various fields in struct proc and struct thread.
  * These are used by kernel debuggers to enumerate kernel threads and
  * processes.
  */
 const int proc_off_p_pid = offsetof(struct proc, p_pid);
 const int proc_off_p_comm = offsetof(struct proc, p_comm);
 const int proc_off_p_list = offsetof(struct proc, p_list);
 const int proc_off_p_hash = offsetof(struct proc, p_hash);
 const int proc_off_p_threads = offsetof(struct proc, p_threads);
 const int thread_off_td_tid = offsetof(struct thread, td_tid);
 const int thread_off_td_name = offsetof(struct thread, td_name);
 const int thread_off_td_oncpu = offsetof(struct thread, td_oncpu);
 const int thread_off_td_pcb = offsetof(struct thread, td_pcb);
 const int thread_off_td_plist = offsetof(struct thread, td_plist);
 
 EVENTHANDLER_LIST_DEFINE(process_ctor);
 EVENTHANDLER_LIST_DEFINE(process_dtor);
 EVENTHANDLER_LIST_DEFINE(process_init);
 EVENTHANDLER_LIST_DEFINE(process_fini);
 EVENTHANDLER_LIST_DEFINE(process_exit);
 EVENTHANDLER_LIST_DEFINE(process_fork);
 EVENTHANDLER_LIST_DEFINE(process_exec);
 
 int kstack_pages = KSTACK_PAGES;
 SYSCTL_INT(_kern, OID_AUTO, kstack_pages, CTLFLAG_RD, &kstack_pages, 0,
     "Kernel stack size in pages");
 static int vmmap_skip_res_cnt = 0;
 SYSCTL_INT(_kern, OID_AUTO, proc_vmmap_skip_resident_count, CTLFLAG_RW,
     &vmmap_skip_res_cnt, 0,
     "Skip calculation of the pages resident count in kern.proc.vmmap");
 
 CTASSERT(sizeof(struct kinfo_proc) == KINFO_PROC_SIZE);
 #ifdef COMPAT_FREEBSD32
 CTASSERT(sizeof(struct kinfo_proc32) == KINFO_PROC32_SIZE);
 #endif
 
 /*
  * Initialize global process hashing structures.
  */
 void
 procinit(void)
 {
 	u_long i;
 
 	sx_init(&allproc_lock, "allproc");
 	sx_init(&proctree_lock, "proctree");
 	mtx_init(&ppeers_lock, "p_peers", NULL, MTX_DEF);
 	mtx_init(&procid_lock, "procid", NULL, MTX_DEF);
-	LIST_INIT(&allproc);
 	pidhashtbl = hashinit(maxproc / 4, M_PROC, &pidhash);
 	pidhashlock = (pidhash + 1) / 64;
 	if (pidhashlock > 0)
 		pidhashlock--;
 	pidhashtbl_lock = malloc(sizeof(*pidhashtbl_lock) * (pidhashlock + 1),
 	    M_PROC, M_WAITOK | M_ZERO);
 	for (i = 0; i < pidhashlock + 1; i++)
 		sx_init_flags(&pidhashtbl_lock[i], "pidhash", SX_DUPOK);
 	pgrphashtbl = hashinit(maxproc / 4, M_PROC, &pgrphash);
 	proc_zone = uma_zcreate("PROC", sched_sizeof_proc(),
 	    proc_ctor, proc_dtor, proc_init, proc_fini,
 	    UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
 	pgrp_zone = uma_zcreate("PGRP", sizeof(struct pgrp), NULL, NULL,
 	    pgrp_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
 	uihashinit();
 }
 
 /*
  * Prepare a proc for use.
  */
 static int
 proc_ctor(void *mem, int size, void *arg, int flags)
 {
 	struct proc *p;
 	struct thread *td;
 
 	p = (struct proc *)mem;
 #ifdef KDTRACE_HOOKS
 	kdtrace_proc_ctor(p);
 #endif
 	EVENTHANDLER_DIRECT_INVOKE(process_ctor, p);
 	td = FIRST_THREAD_IN_PROC(p);
 	if (td != NULL) {
 		/* Make sure all thread constructors are executed */
 		EVENTHANDLER_DIRECT_INVOKE(thread_ctor, td);
 	}
 	return (0);
 }
 
 /*
  * Reclaim a proc after use.
  */
 static void
 proc_dtor(void *mem, int size, void *arg)
 {
 	struct proc *p;
 	struct thread *td;
 
 	/* INVARIANTS checks go here */
 	p = (struct proc *)mem;
 	td = FIRST_THREAD_IN_PROC(p);
 	if (td != NULL) {
 #ifdef INVARIANTS
 		KASSERT((p->p_numthreads == 1),
 		    ("bad number of threads in exiting process"));
 		KASSERT(STAILQ_EMPTY(&p->p_ktr), ("proc_dtor: non-empty p_ktr"));
 #endif
 		/* Free all OSD associated to this thread. */
 		osd_thread_exit(td);
 		td_softdep_cleanup(td);
 		MPASS(td->td_su == NULL);
 
 		/* Make sure all thread destructors are executed */
 		EVENTHANDLER_DIRECT_INVOKE(thread_dtor, td);
 	}
 	EVENTHANDLER_DIRECT_INVOKE(process_dtor, p);
 #ifdef KDTRACE_HOOKS
 	kdtrace_proc_dtor(p);
 #endif
 	if (p->p_ksi != NULL)
 		KASSERT(! KSI_ONQ(p->p_ksi), ("SIGCHLD queue"));
 }
 
 /*
  * Initialize type-stable parts of a proc (when newly created).
  */
 static int
 proc_init(void *mem, int size, int flags)
 {
 	struct proc *p;
 
 	p = (struct proc *)mem;
 	mtx_init(&p->p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK | MTX_NEW);
 	mtx_init(&p->p_slock, "process slock", NULL, MTX_SPIN | MTX_NEW);
 	mtx_init(&p->p_statmtx, "pstatl", NULL, MTX_SPIN | MTX_NEW);
 	mtx_init(&p->p_itimmtx, "pitiml", NULL, MTX_SPIN | MTX_NEW);
 	mtx_init(&p->p_profmtx, "pprofl", NULL, MTX_SPIN | MTX_NEW);
 	cv_init(&p->p_pwait, "ppwait");
 	TAILQ_INIT(&p->p_threads);	     /* all threads in proc */
 	EVENTHANDLER_DIRECT_INVOKE(process_init, p);
 	p->p_stats = pstats_alloc();
 	p->p_pgrp = NULL;
 	return (0);
 }
 
 /*
  * UMA should ensure that this function is never called.
  * Freeing a proc structure would violate type stability.
  */
 static void
 proc_fini(void *mem, int size)
 {
 #ifdef notnow
 	struct proc *p;
 
 	p = (struct proc *)mem;
 	EVENTHANDLER_DIRECT_INVOKE(process_fini, p);
 	pstats_free(p->p_stats);
 	thread_free(FIRST_THREAD_IN_PROC(p));
 	mtx_destroy(&p->p_mtx);
 	if (p->p_ksi != NULL)
 		ksiginfo_free(p->p_ksi);
 #else
 	panic("proc reclaimed");
 #endif
 }
 
 static int
 pgrp_init(void *mem, int size, int flags)
 {
 	struct pgrp *pg;
 
 	pg = mem;
 	mtx_init(&pg->pg_mtx, "process group", NULL, MTX_DEF | MTX_DUPOK);
 	return (0);
 }
 
 /*
  * PID space management.
  *
  * These bitmaps are used by fork_findpid.
  */
 bitstr_t bit_decl(proc_id_pidmap, PID_MAX);
 bitstr_t bit_decl(proc_id_grpidmap, PID_MAX);
 bitstr_t bit_decl(proc_id_sessidmap, PID_MAX);
 bitstr_t bit_decl(proc_id_reapmap, PID_MAX);
 
 static bitstr_t *proc_id_array[] = {
 	proc_id_pidmap,
 	proc_id_grpidmap,
 	proc_id_sessidmap,
 	proc_id_reapmap,
 };
 
 void
 proc_id_set(int type, pid_t id)
 {
 
 	KASSERT(type >= 0 && type < nitems(proc_id_array),
 	    ("invalid type %d\n", type));
 	mtx_lock(&procid_lock);
 	KASSERT(bit_test(proc_id_array[type], id) == 0,
 	    ("bit %d already set in %d\n", id, type));
 	bit_set(proc_id_array[type], id);
 	mtx_unlock(&procid_lock);
 }
 
 void
 proc_id_set_cond(int type, pid_t id)
 {
 
 	KASSERT(type >= 0 && type < nitems(proc_id_array),
 	    ("invalid type %d\n", type));
 	if (bit_test(proc_id_array[type], id))
 		return;
 	mtx_lock(&procid_lock);
 	bit_set(proc_id_array[type], id);
 	mtx_unlock(&procid_lock);
 }
 
 void
 proc_id_clear(int type, pid_t id)
 {
 
 	KASSERT(type >= 0 && type < nitems(proc_id_array),
 	    ("invalid type %d\n", type));
 	mtx_lock(&procid_lock);
 	KASSERT(bit_test(proc_id_array[type], id) != 0,
 	    ("bit %d not set in %d\n", id, type));
 	bit_clear(proc_id_array[type], id);
 	mtx_unlock(&procid_lock);
 }
 
 /*
  * Is p an inferior of the current process?
  */
 int
 inferior(struct proc *p)
 {
 
 	sx_assert(&proctree_lock, SX_LOCKED);
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 	for (; p != curproc; p = proc_realparent(p)) {
 		if (p->p_pid == 0)
 			return (0);
 	}
 	return (1);
 }
 
 /*
  * Shared lock all the pid hash lists.
  */
 void
 pidhash_slockall(void)
 {
 	u_long i;
 
 	for (i = 0; i < pidhashlock + 1; i++)
 		sx_slock(&pidhashtbl_lock[i]);
 }
 
 /*
  * Shared unlock all the pid hash lists.
  */
 void
 pidhash_sunlockall(void)
 {
 	u_long i;
 
 	for (i = 0; i < pidhashlock + 1; i++)
 		sx_sunlock(&pidhashtbl_lock[i]);
 }
 
 /*
  * Similar to pfind_any(), this function finds zombies.
  */
 struct proc *
 pfind_any_locked(pid_t pid)
 {
 	struct proc *p;
 
 	sx_assert(PIDHASHLOCK(pid), SX_LOCKED);
 	LIST_FOREACH(p, PIDHASH(pid), p_hash) {
 		if (p->p_pid == pid) {
 			PROC_LOCK(p);
 			if (p->p_state == PRS_NEW) {
 				PROC_UNLOCK(p);
 				p = NULL;
 			}
 			break;
 		}
 	}
 	return (p);
 }
 
 /*
  * Locate a process by number.
  *
  * By not returning processes in the PRS_NEW state, we allow callers to avoid
  * testing for that condition to avoid dereferencing p_ucred, et al.
  */
 static __always_inline struct proc *
 _pfind(pid_t pid, bool zombie)
 {
 	struct proc *p;
 
 	p = curproc;
 	if (p->p_pid == pid) {
 		PROC_LOCK(p);
 		return (p);
 	}
 	sx_slock(PIDHASHLOCK(pid));
 	LIST_FOREACH(p, PIDHASH(pid), p_hash) {
 		if (p->p_pid == pid) {
 			PROC_LOCK(p);
 			if (p->p_state == PRS_NEW ||
 			    (!zombie && p->p_state == PRS_ZOMBIE)) {
 				PROC_UNLOCK(p);
 				p = NULL;
 			}
 			break;
 		}
 	}
 	sx_sunlock(PIDHASHLOCK(pid));
 	return (p);
 }
 
 struct proc *
 pfind(pid_t pid)
 {
 
 	return (_pfind(pid, false));
 }
 
 /*
  * Same as pfind but allow zombies.
  */
 struct proc *
 pfind_any(pid_t pid)
 {
 
 	return (_pfind(pid, true));
 }
 
 /*
  * Locate a process group by number.
  * The caller must hold proctree_lock.
  */
 struct pgrp *
 pgfind(pid_t pgid)
 {
 	struct pgrp *pgrp;
 
 	sx_assert(&proctree_lock, SX_LOCKED);
 
 	LIST_FOREACH(pgrp, PGRPHASH(pgid), pg_hash) {
 		if (pgrp->pg_id == pgid) {
 			PGRP_LOCK(pgrp);
 			return (pgrp);
 		}
 	}
 	return (NULL);
 }
 
 /*
  * Locate process and do additional manipulations, depending on flags.
  */
 int
 pget(pid_t pid, int flags, struct proc **pp)
 {
 	struct proc *p;
 	struct thread *td1;
 	int error;
 
 	p = curproc;
 	if (p->p_pid == pid) {
 		PROC_LOCK(p);
 	} else {
 		p = NULL;
 		if (pid <= PID_MAX) {
 			if ((flags & PGET_NOTWEXIT) == 0)
 				p = pfind_any(pid);
 			else
 				p = pfind(pid);
 		} else if ((flags & PGET_NOTID) == 0) {
 			td1 = tdfind(pid, -1);
 			if (td1 != NULL)
 				p = td1->td_proc;
 		}
 		if (p == NULL)
 			return (ESRCH);
 		if ((flags & PGET_CANSEE) != 0) {
 			error = p_cansee(curthread, p);
 			if (error != 0)
 				goto errout;
 		}
 	}
 	if ((flags & PGET_CANDEBUG) != 0) {
 		error = p_candebug(curthread, p);
 		if (error != 0)
 			goto errout;
 	}
 	if ((flags & PGET_ISCURRENT) != 0 && curproc != p) {
 		error = EPERM;
 		goto errout;
 	}
 	if ((flags & PGET_NOTWEXIT) != 0 && (p->p_flag & P_WEXIT) != 0) {
 		error = ESRCH;
 		goto errout;
 	}
 	if ((flags & PGET_NOTINEXEC) != 0 && (p->p_flag & P_INEXEC) != 0) {
 		/*
 		 * XXXRW: Not clear ESRCH is the right error during proc
 		 * execve().
 		 */
 		error = ESRCH;
 		goto errout;
 	}
 	if ((flags & PGET_HOLD) != 0) {
 		_PHOLD(p);
 		PROC_UNLOCK(p);
 	}
 	*pp = p;
 	return (0);
 errout:
 	PROC_UNLOCK(p);
 	return (error);
 }
 
 /*
  * Create a new process group.
  * pgid must be equal to the pid of p.
  * Begin a new session if required.
  */
 int
 enterpgrp(struct proc *p, pid_t pgid, struct pgrp *pgrp, struct session *sess)
 {
 
 	sx_assert(&proctree_lock, SX_XLOCKED);
 
 	KASSERT(pgrp != NULL, ("enterpgrp: pgrp == NULL"));
 	KASSERT(p->p_pid == pgid,
 	    ("enterpgrp: new pgrp and pid != pgid"));
 	KASSERT(pgfind(pgid) == NULL,
 	    ("enterpgrp: pgrp with pgid exists"));
 	KASSERT(!SESS_LEADER(p),
 	    ("enterpgrp: session leader attempted setpgrp"));
 
 	if (sess != NULL) {
 		/*
 		 * new session
 		 */
 		mtx_init(&sess->s_mtx, "session", NULL, MTX_DEF);
 		PROC_LOCK(p);
 		p->p_flag &= ~P_CONTROLT;
 		PROC_UNLOCK(p);
 		PGRP_LOCK(pgrp);
 		sess->s_leader = p;
 		sess->s_sid = p->p_pid;
 		proc_id_set(PROC_ID_SESSION, p->p_pid);
 		refcount_init(&sess->s_count, 1);
 		sess->s_ttyvp = NULL;
 		sess->s_ttydp = NULL;
 		sess->s_ttyp = NULL;
 		bcopy(p->p_session->s_login, sess->s_login,
 			    sizeof(sess->s_login));
 		pgrp->pg_session = sess;
 		KASSERT(p == curproc,
 		    ("enterpgrp: mksession and p != curproc"));
 	} else {
 		pgrp->pg_session = p->p_session;
 		sess_hold(pgrp->pg_session);
 		PGRP_LOCK(pgrp);
 	}
 	pgrp->pg_id = pgid;
 	proc_id_set(PROC_ID_GROUP, p->p_pid);
 	LIST_INIT(&pgrp->pg_members);
 	pgrp->pg_flags = 0;
 
 	/*
 	 * As we have an exclusive lock of proctree_lock,
 	 * this should not deadlock.
 	 */
 	LIST_INSERT_HEAD(PGRPHASH(pgid), pgrp, pg_hash);
 	SLIST_INIT(&pgrp->pg_sigiolst);
 	PGRP_UNLOCK(pgrp);
 
 	doenterpgrp(p, pgrp);
 
 	return (0);
 }
 
 /*
  * Move p to an existing process group
  */
 int
 enterthispgrp(struct proc *p, struct pgrp *pgrp)
 {
 
 	sx_assert(&proctree_lock, SX_XLOCKED);
 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
 	PGRP_LOCK_ASSERT(pgrp, MA_NOTOWNED);
 	PGRP_LOCK_ASSERT(p->p_pgrp, MA_NOTOWNED);
 	SESS_LOCK_ASSERT(p->p_session, MA_NOTOWNED);
 	KASSERT(pgrp->pg_session == p->p_session,
 	    ("%s: pgrp's session %p, p->p_session %p proc %p\n",
 	    __func__, pgrp->pg_session, p->p_session, p));
 	KASSERT(pgrp != p->p_pgrp,
 	    ("%s: p %p belongs to pgrp %p", __func__, p, pgrp));
 
 	doenterpgrp(p, pgrp);
 
 	return (0);
 }
 
 /*
  * If true, any child of q which belongs to group pgrp, qualifies the
  * process group pgrp as not orphaned.
  */
 static bool
 isjobproc(struct proc *q, struct pgrp *pgrp)
 {
 	sx_assert(&proctree_lock, SX_LOCKED);
 
 	return (q->p_pgrp != pgrp &&
 	    q->p_pgrp->pg_session == pgrp->pg_session);
 }
 
 static struct proc *
 jobc_reaper(struct proc *p)
 {
 	struct proc *pp;
 
 	sx_assert(&proctree_lock, SA_LOCKED);
 
 	for (pp = p;;) {
 		pp = pp->p_reaper;
 		if (pp->p_reaper == pp ||
 		    (pp->p_treeflag & P_TREE_GRPEXITED) == 0)
 			return (pp);
 	}
 }
 
 static struct proc *
 jobc_parent(struct proc *p, struct proc *p_exiting)
 {
 	struct proc *pp;
 
 	sx_assert(&proctree_lock, SA_LOCKED);
 
 	pp = proc_realparent(p);
 	if (pp->p_pptr == NULL || pp == p_exiting ||
 	    (pp->p_treeflag & P_TREE_GRPEXITED) == 0)
 		return (pp);
 	return (jobc_reaper(pp));
 }
 
 static int
 pgrp_calc_jobc(struct pgrp *pgrp)
 {
 	struct proc *q;
 	int cnt;
 
 #ifdef INVARIANTS
 	if (!mtx_owned(&pgrp->pg_mtx))
 		sx_assert(&proctree_lock, SA_LOCKED);
 #endif
 
 	cnt = 0;
 	LIST_FOREACH(q, &pgrp->pg_members, p_pglist) {
 		if ((q->p_treeflag & P_TREE_GRPEXITED) != 0 ||
 		    q->p_pptr == NULL)
 			continue;
 		if (isjobproc(jobc_parent(q, NULL), pgrp))
 			cnt++;
 	}
 	return (cnt);
 }
 
 /*
  * Move p to a process group
  */
 static void
 doenterpgrp(struct proc *p, struct pgrp *pgrp)
 {
 	struct pgrp *savepgrp;
 	struct proc *pp;
 
 	sx_assert(&proctree_lock, SX_XLOCKED);
 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
 	PGRP_LOCK_ASSERT(pgrp, MA_NOTOWNED);
 	PGRP_LOCK_ASSERT(p->p_pgrp, MA_NOTOWNED);
 	SESS_LOCK_ASSERT(p->p_session, MA_NOTOWNED);
 
 	savepgrp = p->p_pgrp;
 	pp = jobc_parent(p, NULL);
 
 	PGRP_LOCK(pgrp);
 	PGRP_LOCK(savepgrp);
 	if (isjobproc(pp, savepgrp) && pgrp_calc_jobc(savepgrp) == 1)
 		orphanpg(savepgrp);
 	PROC_LOCK(p);
 	LIST_REMOVE(p, p_pglist);
 	p->p_pgrp = pgrp;
 	PROC_UNLOCK(p);
 	LIST_INSERT_HEAD(&pgrp->pg_members, p, p_pglist);
 	if (isjobproc(pp, pgrp))
 		pgrp->pg_flags &= ~PGRP_ORPHANED;
 	PGRP_UNLOCK(savepgrp);
 	PGRP_UNLOCK(pgrp);
 	if (LIST_EMPTY(&savepgrp->pg_members))
 		pgdelete(savepgrp);
 }
 
 /*
  * remove process from process group
  */
 int
 leavepgrp(struct proc *p)
 {
 	struct pgrp *savepgrp;
 
 	sx_assert(&proctree_lock, SX_XLOCKED);
 	savepgrp = p->p_pgrp;
 	PGRP_LOCK(savepgrp);
 	PROC_LOCK(p);
 	LIST_REMOVE(p, p_pglist);
 	p->p_pgrp = NULL;
 	PROC_UNLOCK(p);
 	PGRP_UNLOCK(savepgrp);
 	if (LIST_EMPTY(&savepgrp->pg_members))
 		pgdelete(savepgrp);
 	return (0);
 }
 
 /*
  * delete a process group
  */
 static void
 pgdelete(struct pgrp *pgrp)
 {
 	struct session *savesess;
 	struct tty *tp;
 
 	sx_assert(&proctree_lock, SX_XLOCKED);
 	PGRP_LOCK_ASSERT(pgrp, MA_NOTOWNED);
 	SESS_LOCK_ASSERT(pgrp->pg_session, MA_NOTOWNED);
 
 	/*
 	 * Reset any sigio structures pointing to us as a result of
 	 * F_SETOWN with our pgid.  The proctree lock ensures that
 	 * new sigio structures will not be added after this point.
 	 */
 	funsetownlst(&pgrp->pg_sigiolst);
 
 	PGRP_LOCK(pgrp);
 	tp = pgrp->pg_session->s_ttyp;
 	LIST_REMOVE(pgrp, pg_hash);
 	savesess = pgrp->pg_session;
 	PGRP_UNLOCK(pgrp);
 
 	/* Remove the reference to the pgrp before deallocating it. */
 	if (tp != NULL) {
 		tty_lock(tp);
 		tty_rel_pgrp(tp, pgrp);
 	}
 
 	proc_id_clear(PROC_ID_GROUP, pgrp->pg_id);
 	uma_zfree(pgrp_zone, pgrp);
 	sess_release(savesess);
 }
 
 
 static void
 fixjobc_kill(struct proc *p)
 {
 	struct proc *q;
 	struct pgrp *pgrp;
 
 	sx_assert(&proctree_lock, SX_LOCKED);
 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
 	pgrp = p->p_pgrp;
 	PGRP_LOCK_ASSERT(pgrp, MA_NOTOWNED);
 	SESS_LOCK_ASSERT(pgrp->pg_session, MA_NOTOWNED);
 
 	/*
 	 * p no longer affects process group orphanage for children.
 	 * It is marked by the flag because p is only physically
 	 * removed from its process group on wait(2).
 	 */
 	MPASS((p->p_treeflag & P_TREE_GRPEXITED) == 0);
 	p->p_treeflag |= P_TREE_GRPEXITED;
 
 	/*
 	 * Check if exiting p orphans its own group.
 	 */
 	pgrp = p->p_pgrp;
 	if (isjobproc(jobc_parent(p, NULL), pgrp)) {
 		PGRP_LOCK(pgrp);
 		if (pgrp_calc_jobc(pgrp) == 0)
 			orphanpg(pgrp);
 		PGRP_UNLOCK(pgrp);
 	}
 
 	/*
 	 * Check this process' children to see whether they qualify
 	 * their process groups after reparenting to reaper.
 	 */
 	LIST_FOREACH(q, &p->p_children, p_sibling) {
 		pgrp = q->p_pgrp;
 		PGRP_LOCK(pgrp);
 		if (pgrp_calc_jobc(pgrp) == 0) {
 			/*
 			 * We want to handle exactly the children that
 			 * has p as realparent.  Then, when calculating
 			 * jobc_parent for children, we should ignore
 			 * P_TREE_GRPEXITED flag already set on p.
 			 */
 			if (jobc_parent(q, p) == p && isjobproc(p, pgrp))
 				orphanpg(pgrp);
 		} else
 			pgrp->pg_flags &= ~PGRP_ORPHANED;
 		PGRP_UNLOCK(pgrp);
 	}
 	LIST_FOREACH(q, &p->p_orphans, p_orphan) {
 		pgrp = q->p_pgrp;
 		PGRP_LOCK(pgrp);
 		if (pgrp_calc_jobc(pgrp) == 0) {
 			if (isjobproc(p, pgrp))
 				orphanpg(pgrp);
 		} else
 			pgrp->pg_flags &= ~PGRP_ORPHANED;
 		PGRP_UNLOCK(pgrp);
 	}
 }
 
 void
 killjobc(void)
 {
 	struct session *sp;
 	struct tty *tp;
 	struct proc *p;
 	struct vnode *ttyvp;
 
 	p = curproc;
 	MPASS(p->p_flag & P_WEXIT);
 	sx_assert(&proctree_lock, SX_LOCKED);
 
 	if (SESS_LEADER(p)) {
 		sp = p->p_session;
 
 		/*
 		 * s_ttyp is not zero'd; we use this to indicate that
 		 * the session once had a controlling terminal. (for
 		 * logging and informational purposes)
 		 */
 		SESS_LOCK(sp);
 		ttyvp = sp->s_ttyvp;
 		tp = sp->s_ttyp;
 		sp->s_ttyvp = NULL;
 		sp->s_ttydp = NULL;
 		sp->s_leader = NULL;
 		SESS_UNLOCK(sp);
 
 		/*
 		 * Signal foreground pgrp and revoke access to
 		 * controlling terminal if it has not been revoked
 		 * already.
 		 *
 		 * Because the TTY may have been revoked in the mean
 		 * time and could already have a new session associated
 		 * with it, make sure we don't send a SIGHUP to a
 		 * foreground process group that does not belong to this
 		 * session.
 		 */
 
 		if (tp != NULL) {
 			tty_lock(tp);
 			if (tp->t_session == sp)
 				tty_signal_pgrp(tp, SIGHUP);
 			tty_unlock(tp);
 		}
 
 		if (ttyvp != NULL) {
 			sx_xunlock(&proctree_lock);
 			if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) {
 				VOP_REVOKE(ttyvp, REVOKEALL);
 				VOP_UNLOCK(ttyvp);
 			}
 			devfs_ctty_unref(ttyvp);
 			sx_xlock(&proctree_lock);
 		}
 	}
 	fixjobc_kill(p);
 }
 
 /*
  * A process group has become orphaned, mark it as such for signal
  * delivery code.  If there are any stopped processes in the group,
  * hang-up all process in that group.
  */
 static void
 orphanpg(struct pgrp *pg)
 {
 	struct proc *p;
 
 	PGRP_LOCK_ASSERT(pg, MA_OWNED);
 
 	pg->pg_flags |= PGRP_ORPHANED;
 
 	LIST_FOREACH(p, &pg->pg_members, p_pglist) {
 		PROC_LOCK(p);
 		if (P_SHOULDSTOP(p) == P_STOPPED_SIG) {
 			PROC_UNLOCK(p);
 			LIST_FOREACH(p, &pg->pg_members, p_pglist) {
 				PROC_LOCK(p);
 				kern_psignal(p, SIGHUP);
 				kern_psignal(p, SIGCONT);
 				PROC_UNLOCK(p);
 			}
 			return;
 		}
 		PROC_UNLOCK(p);
 	}
 }
 
 void
 sess_hold(struct session *s)
 {
 
 	refcount_acquire(&s->s_count);
 }
 
 void
 sess_release(struct session *s)
 {
 
 	if (refcount_release(&s->s_count)) {
 		if (s->s_ttyp != NULL) {
 			tty_lock(s->s_ttyp);
 			tty_rel_sess(s->s_ttyp, s);
 		}
 		proc_id_clear(PROC_ID_SESSION, s->s_sid);
 		mtx_destroy(&s->s_mtx);
 		free(s, M_SESSION);
 	}
 }
 
 #ifdef DDB
 
 static void
 db_print_pgrp_one(struct pgrp *pgrp, struct proc *p)
 {
 	db_printf(
 	    "    pid %d at %p pr %d pgrp %p e %d jc %d\n",
 	    p->p_pid, p, p->p_pptr == NULL ? -1 : p->p_pptr->p_pid,
 	    p->p_pgrp, (p->p_treeflag & P_TREE_GRPEXITED) != 0,
 	    p->p_pptr == NULL ? 0 : isjobproc(p->p_pptr, pgrp));
 }
 
 DB_SHOW_COMMAND(pgrpdump, pgrpdump)
 {
 	struct pgrp *pgrp;
 	struct proc *p;
 	int i;
 
 	for (i = 0; i <= pgrphash; i++) {
 		if (!LIST_EMPTY(&pgrphashtbl[i])) {
 			db_printf("indx %d\n", i);
 			LIST_FOREACH(pgrp, &pgrphashtbl[i], pg_hash) {
 				db_printf(
 			"  pgrp %p, pgid %d, sess %p, sesscnt %d, mem %p\n",
 				    pgrp, (int)pgrp->pg_id, pgrp->pg_session,
 				    pgrp->pg_session->s_count,
 				    LIST_FIRST(&pgrp->pg_members));
 				LIST_FOREACH(p, &pgrp->pg_members, p_pglist)
 					db_print_pgrp_one(pgrp, p);
 			}
 		}
 	}
 }
 #endif /* DDB */
 
 /*
  * Calculate the kinfo_proc members which contain process-wide
  * informations.
  * Must be called with the target process locked.
  */
 static void
 fill_kinfo_aggregate(struct proc *p, struct kinfo_proc *kp)
 {
 	struct thread *td;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 
 	kp->ki_estcpu = 0;
 	kp->ki_pctcpu = 0;
 	FOREACH_THREAD_IN_PROC(p, td) {
 		thread_lock(td);
 		kp->ki_pctcpu += sched_pctcpu(td);
 		kp->ki_estcpu += sched_estcpu(td);
 		thread_unlock(td);
 	}
 }
 
 /*
  * Fill in any information that is common to all threads in the process.
  * Must be called with the target process locked.
  */
 static void
 fill_kinfo_proc_only(struct proc *p, struct kinfo_proc *kp)
 {
 	struct thread *td0;
 	struct ucred *cred;
 	struct sigacts *ps;
 	struct timeval boottime;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 
 	kp->ki_structsize = sizeof(*kp);
 	kp->ki_paddr = p;
 	kp->ki_addr =/* p->p_addr; */0; /* XXX */
 	kp->ki_args = p->p_args;
 	kp->ki_textvp = p->p_textvp;
 #ifdef KTRACE
 	kp->ki_tracep = ktr_get_tracevp(p, false);
 	kp->ki_traceflag = p->p_traceflag;
 #endif
 	kp->ki_fd = p->p_fd;
 	kp->ki_pd = p->p_pd;
 	kp->ki_vmspace = p->p_vmspace;
 	kp->ki_flag = p->p_flag;
 	kp->ki_flag2 = p->p_flag2;
 	cred = p->p_ucred;
 	if (cred) {
 		kp->ki_uid = cred->cr_uid;
 		kp->ki_ruid = cred->cr_ruid;
 		kp->ki_svuid = cred->cr_svuid;
 		kp->ki_cr_flags = 0;
 		if (cred->cr_flags & CRED_FLAG_CAPMODE)
 			kp->ki_cr_flags |= KI_CRF_CAPABILITY_MODE;
 		/* XXX bde doesn't like KI_NGROUPS */
 		if (cred->cr_ngroups > KI_NGROUPS) {
 			kp->ki_ngroups = KI_NGROUPS;
 			kp->ki_cr_flags |= KI_CRF_GRP_OVERFLOW;
 		} else
 			kp->ki_ngroups = cred->cr_ngroups;
 		bcopy(cred->cr_groups, kp->ki_groups,
 		    kp->ki_ngroups * sizeof(gid_t));
 		kp->ki_rgid = cred->cr_rgid;
 		kp->ki_svgid = cred->cr_svgid;
 		/* If jailed(cred), emulate the old P_JAILED flag. */
 		if (jailed(cred)) {
 			kp->ki_flag |= P_JAILED;
 			/* If inside the jail, use 0 as a jail ID. */
 			if (cred->cr_prison != curthread->td_ucred->cr_prison)
 				kp->ki_jid = cred->cr_prison->pr_id;
 		}
 		strlcpy(kp->ki_loginclass, cred->cr_loginclass->lc_name,
 		    sizeof(kp->ki_loginclass));
 	}
 	ps = p->p_sigacts;
 	if (ps) {
 		mtx_lock(&ps->ps_mtx);
 		kp->ki_sigignore = ps->ps_sigignore;
 		kp->ki_sigcatch = ps->ps_sigcatch;
 		mtx_unlock(&ps->ps_mtx);
 	}
 	if (p->p_state != PRS_NEW &&
 	    p->p_state != PRS_ZOMBIE &&
 	    p->p_vmspace != NULL) {
 		struct vmspace *vm = p->p_vmspace;
 
 		kp->ki_size = vm->vm_map.size;
 		kp->ki_rssize = vmspace_resident_count(vm); /*XXX*/
 		FOREACH_THREAD_IN_PROC(p, td0) {
 			if (!TD_IS_SWAPPED(td0))
 				kp->ki_rssize += td0->td_kstack_pages;
 		}
 		kp->ki_swrss = vm->vm_swrss;
 		kp->ki_tsize = vm->vm_tsize;
 		kp->ki_dsize = vm->vm_dsize;
 		kp->ki_ssize = vm->vm_ssize;
 	} else if (p->p_state == PRS_ZOMBIE)
 		kp->ki_stat = SZOMB;
 	if (kp->ki_flag & P_INMEM)
 		kp->ki_sflag = PS_INMEM;
 	else
 		kp->ki_sflag = 0;
 	/* Calculate legacy swtime as seconds since 'swtick'. */
 	kp->ki_swtime = (ticks - p->p_swtick) / hz;
 	kp->ki_pid = p->p_pid;
 	kp->ki_nice = p->p_nice;
 	kp->ki_fibnum = p->p_fibnum;
 	kp->ki_start = p->p_stats->p_start;
 	getboottime(&boottime);
 	timevaladd(&kp->ki_start, &boottime);
 	PROC_STATLOCK(p);
 	rufetch(p, &kp->ki_rusage);
 	kp->ki_runtime = cputick2usec(p->p_rux.rux_runtime);
 	calcru(p, &kp->ki_rusage.ru_utime, &kp->ki_rusage.ru_stime);
 	PROC_STATUNLOCK(p);
 	calccru(p, &kp->ki_childutime, &kp->ki_childstime);
 	/* Some callers want child times in a single value. */
 	kp->ki_childtime = kp->ki_childstime;
 	timevaladd(&kp->ki_childtime, &kp->ki_childutime);
 
 	FOREACH_THREAD_IN_PROC(p, td0)
 		kp->ki_cow += td0->td_cow;
 
 	if (p->p_comm[0] != '\0')
 		strlcpy(kp->ki_comm, p->p_comm, sizeof(kp->ki_comm));
 	if (p->p_sysent && p->p_sysent->sv_name != NULL &&
 	    p->p_sysent->sv_name[0] != '\0')
 		strlcpy(kp->ki_emul, p->p_sysent->sv_name, sizeof(kp->ki_emul));
 	kp->ki_siglist = p->p_siglist;
 	kp->ki_xstat = KW_EXITCODE(p->p_xexit, p->p_xsig);
 	kp->ki_acflag = p->p_acflag;
 	kp->ki_lock = p->p_lock;
 	if (p->p_pptr) {
 		kp->ki_ppid = p->p_oppid;
 		if (p->p_flag & P_TRACED)
 			kp->ki_tracer = p->p_pptr->p_pid;
 	}
 }
 
 /*
  * Fill job-related process information.
  */
 static void
 fill_kinfo_proc_pgrp(struct proc *p, struct kinfo_proc *kp)
 {
 	struct tty *tp;
 	struct session *sp;
 	struct pgrp *pgrp;
 
 	sx_assert(&proctree_lock, SA_LOCKED);
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 
 	pgrp = p->p_pgrp;
 	if (pgrp == NULL)
 		return;
 
 	kp->ki_pgid = pgrp->pg_id;
 	kp->ki_jobc = pgrp_calc_jobc(pgrp);
 
 	sp = pgrp->pg_session;
 	tp = NULL;
 
 	if (sp != NULL) {
 		kp->ki_sid = sp->s_sid;
 		SESS_LOCK(sp);
 		strlcpy(kp->ki_login, sp->s_login, sizeof(kp->ki_login));
 		if (sp->s_ttyvp)
 			kp->ki_kiflag |= KI_CTTY;
 		if (SESS_LEADER(p))
 			kp->ki_kiflag |= KI_SLEADER;
 		tp = sp->s_ttyp;
 		SESS_UNLOCK(sp);
 	}
 
 	if ((p->p_flag & P_CONTROLT) && tp != NULL) {
 		kp->ki_tdev = tty_udev(tp);
 		kp->ki_tdev_freebsd11 = kp->ki_tdev; /* truncate */
 		kp->ki_tpgid = tp->t_pgrp ? tp->t_pgrp->pg_id : NO_PID;
 		if (tp->t_session)
 			kp->ki_tsid = tp->t_session->s_sid;
 	} else {
 		kp->ki_tdev = NODEV;
 		kp->ki_tdev_freebsd11 = kp->ki_tdev; /* truncate */
 	}
 }
 
 /*
  * Fill in information that is thread specific.  Must be called with
  * target process locked.  If 'preferthread' is set, overwrite certain
  * process-related fields that are maintained for both threads and
  * processes.
  */
 static void
 fill_kinfo_thread(struct thread *td, struct kinfo_proc *kp, int preferthread)
 {
 	struct proc *p;
 
 	p = td->td_proc;
 	kp->ki_tdaddr = td;
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 
 	if (preferthread)
 		PROC_STATLOCK(p);
 	thread_lock(td);
 	if (td->td_wmesg != NULL)
 		strlcpy(kp->ki_wmesg, td->td_wmesg, sizeof(kp->ki_wmesg));
 	else
 		bzero(kp->ki_wmesg, sizeof(kp->ki_wmesg));
 	if (strlcpy(kp->ki_tdname, td->td_name, sizeof(kp->ki_tdname)) >=
 	    sizeof(kp->ki_tdname)) {
 		strlcpy(kp->ki_moretdname,
 		    td->td_name + sizeof(kp->ki_tdname) - 1,
 		    sizeof(kp->ki_moretdname));
 	} else {
 		bzero(kp->ki_moretdname, sizeof(kp->ki_moretdname));
 	}
 	if (TD_ON_LOCK(td)) {
 		kp->ki_kiflag |= KI_LOCKBLOCK;
 		strlcpy(kp->ki_lockname, td->td_lockname,
 		    sizeof(kp->ki_lockname));
 	} else {
 		kp->ki_kiflag &= ~KI_LOCKBLOCK;
 		bzero(kp->ki_lockname, sizeof(kp->ki_lockname));
 	}
 
 	if (p->p_state == PRS_NORMAL) { /* approximate. */
 		if (TD_ON_RUNQ(td) ||
 		    TD_CAN_RUN(td) ||
 		    TD_IS_RUNNING(td)) {
 			kp->ki_stat = SRUN;
 		} else if (P_SHOULDSTOP(p)) {
 			kp->ki_stat = SSTOP;
 		} else if (TD_IS_SLEEPING(td)) {
 			kp->ki_stat = SSLEEP;
 		} else if (TD_ON_LOCK(td)) {
 			kp->ki_stat = SLOCK;
 		} else {
 			kp->ki_stat = SWAIT;
 		}
 	} else if (p->p_state == PRS_ZOMBIE) {
 		kp->ki_stat = SZOMB;
 	} else {
 		kp->ki_stat = SIDL;
 	}
 
 	/* Things in the thread */
 	kp->ki_wchan = td->td_wchan;
 	kp->ki_pri.pri_level = td->td_priority;
 	kp->ki_pri.pri_native = td->td_base_pri;
 
 	/*
 	 * Note: legacy fields; clamp at the old NOCPU value and/or
 	 * the maximum u_char CPU value.
 	 */
 	if (td->td_lastcpu == NOCPU)
 		kp->ki_lastcpu_old = NOCPU_OLD;
 	else if (td->td_lastcpu > MAXCPU_OLD)
 		kp->ki_lastcpu_old = MAXCPU_OLD;
 	else
 		kp->ki_lastcpu_old = td->td_lastcpu;
 
 	if (td->td_oncpu == NOCPU)
 		kp->ki_oncpu_old = NOCPU_OLD;
 	else if (td->td_oncpu > MAXCPU_OLD)
 		kp->ki_oncpu_old = MAXCPU_OLD;
 	else
 		kp->ki_oncpu_old = td->td_oncpu;
 
 	kp->ki_lastcpu = td->td_lastcpu;
 	kp->ki_oncpu = td->td_oncpu;
 	kp->ki_tdflags = td->td_flags;
 	kp->ki_tid = td->td_tid;
 	kp->ki_numthreads = p->p_numthreads;
 	kp->ki_pcb = td->td_pcb;
 	kp->ki_kstack = (void *)td->td_kstack;
 	kp->ki_slptime = (ticks - td->td_slptick) / hz;
 	kp->ki_pri.pri_class = td->td_pri_class;
 	kp->ki_pri.pri_user = td->td_user_pri;
 
 	if (preferthread) {
 		rufetchtd(td, &kp->ki_rusage);
 		kp->ki_runtime = cputick2usec(td->td_rux.rux_runtime);
 		kp->ki_pctcpu = sched_pctcpu(td);
 		kp->ki_estcpu = sched_estcpu(td);
 		kp->ki_cow = td->td_cow;
 	}
 
 	/* We can't get this anymore but ps etc never used it anyway. */
 	kp->ki_rqindex = 0;
 
 	if (preferthread)
 		kp->ki_siglist = td->td_siglist;
 	kp->ki_sigmask = td->td_sigmask;
 	thread_unlock(td);
 	if (preferthread)
 		PROC_STATUNLOCK(p);
 }
 
 /*
  * Fill in a kinfo_proc structure for the specified process.
  * Must be called with the target process locked.
  */
 void
 fill_kinfo_proc(struct proc *p, struct kinfo_proc *kp)
 {
 	MPASS(FIRST_THREAD_IN_PROC(p) != NULL);
 
 	bzero(kp, sizeof(*kp));
 
 	fill_kinfo_proc_pgrp(p,kp);
 	fill_kinfo_proc_only(p, kp);
 	fill_kinfo_thread(FIRST_THREAD_IN_PROC(p), kp, 0);
 	fill_kinfo_aggregate(p, kp);
 }
 
 struct pstats *
 pstats_alloc(void)
 {
 
 	return (malloc(sizeof(struct pstats), M_SUBPROC, M_ZERO|M_WAITOK));
 }
 
 /*
  * Copy parts of p_stats; zero the rest of p_stats (statistics).
  */
 void
 pstats_fork(struct pstats *src, struct pstats *dst)
 {
 
 	bzero(&dst->pstat_startzero,
 	    __rangeof(struct pstats, pstat_startzero, pstat_endzero));
 	bcopy(&src->pstat_startcopy, &dst->pstat_startcopy,
 	    __rangeof(struct pstats, pstat_startcopy, pstat_endcopy));
 }
 
 void
 pstats_free(struct pstats *ps)
 {
 
 	free(ps, M_SUBPROC);
 }
 
 #ifdef COMPAT_FREEBSD32
 
 /*
  * This function is typically used to copy out the kernel address, so
  * it can be replaced by assignment of zero.
  */
 static inline uint32_t
 ptr32_trim(const void *ptr)
 {
 	uintptr_t uptr;
 
 	uptr = (uintptr_t)ptr;
 	return ((uptr > UINT_MAX) ? 0 : uptr);
 }
 
 #define PTRTRIM_CP(src,dst,fld) \
 	do { (dst).fld = ptr32_trim((src).fld); } while (0)
 
 static void
 freebsd32_kinfo_proc_out(const struct kinfo_proc *ki, struct kinfo_proc32 *ki32)
 {
 	int i;
 
 	bzero(ki32, sizeof(struct kinfo_proc32));
 	ki32->ki_structsize = sizeof(struct kinfo_proc32);
 	CP(*ki, *ki32, ki_layout);
 	PTRTRIM_CP(*ki, *ki32, ki_args);
 	PTRTRIM_CP(*ki, *ki32, ki_paddr);
 	PTRTRIM_CP(*ki, *ki32, ki_addr);
 	PTRTRIM_CP(*ki, *ki32, ki_tracep);
 	PTRTRIM_CP(*ki, *ki32, ki_textvp);
 	PTRTRIM_CP(*ki, *ki32, ki_fd);
 	PTRTRIM_CP(*ki, *ki32, ki_vmspace);
 	PTRTRIM_CP(*ki, *ki32, ki_wchan);
 	CP(*ki, *ki32, ki_pid);
 	CP(*ki, *ki32, ki_ppid);
 	CP(*ki, *ki32, ki_pgid);
 	CP(*ki, *ki32, ki_tpgid);
 	CP(*ki, *ki32, ki_sid);
 	CP(*ki, *ki32, ki_tsid);
 	CP(*ki, *ki32, ki_jobc);
 	CP(*ki, *ki32, ki_tdev);
 	CP(*ki, *ki32, ki_tdev_freebsd11);
 	CP(*ki, *ki32, ki_siglist);
 	CP(*ki, *ki32, ki_sigmask);
 	CP(*ki, *ki32, ki_sigignore);
 	CP(*ki, *ki32, ki_sigcatch);
 	CP(*ki, *ki32, ki_uid);
 	CP(*ki, *ki32, ki_ruid);
 	CP(*ki, *ki32, ki_svuid);
 	CP(*ki, *ki32, ki_rgid);
 	CP(*ki, *ki32, ki_svgid);
 	CP(*ki, *ki32, ki_ngroups);
 	for (i = 0; i < KI_NGROUPS; i++)
 		CP(*ki, *ki32, ki_groups[i]);
 	CP(*ki, *ki32, ki_size);
 	CP(*ki, *ki32, ki_rssize);
 	CP(*ki, *ki32, ki_swrss);
 	CP(*ki, *ki32, ki_tsize);
 	CP(*ki, *ki32, ki_dsize);
 	CP(*ki, *ki32, ki_ssize);
 	CP(*ki, *ki32, ki_xstat);
 	CP(*ki, *ki32, ki_acflag);
 	CP(*ki, *ki32, ki_pctcpu);
 	CP(*ki, *ki32, ki_estcpu);
 	CP(*ki, *ki32, ki_slptime);
 	CP(*ki, *ki32, ki_swtime);
 	CP(*ki, *ki32, ki_cow);
 	CP(*ki, *ki32, ki_runtime);
 	TV_CP(*ki, *ki32, ki_start);
 	TV_CP(*ki, *ki32, ki_childtime);
 	CP(*ki, *ki32, ki_flag);
 	CP(*ki, *ki32, ki_kiflag);
 	CP(*ki, *ki32, ki_traceflag);
 	CP(*ki, *ki32, ki_stat);
 	CP(*ki, *ki32, ki_nice);
 	CP(*ki, *ki32, ki_lock);
 	CP(*ki, *ki32, ki_rqindex);
 	CP(*ki, *ki32, ki_oncpu);
 	CP(*ki, *ki32, ki_lastcpu);
 
 	/* XXX TODO: wrap cpu value as appropriate */
 	CP(*ki, *ki32, ki_oncpu_old);
 	CP(*ki, *ki32, ki_lastcpu_old);
 
 	bcopy(ki->ki_tdname, ki32->ki_tdname, TDNAMLEN + 1);
 	bcopy(ki->ki_wmesg, ki32->ki_wmesg, WMESGLEN + 1);
 	bcopy(ki->ki_login, ki32->ki_login, LOGNAMELEN + 1);
 	bcopy(ki->ki_lockname, ki32->ki_lockname, LOCKNAMELEN + 1);
 	bcopy(ki->ki_comm, ki32->ki_comm, COMMLEN + 1);
 	bcopy(ki->ki_emul, ki32->ki_emul, KI_EMULNAMELEN + 1);
 	bcopy(ki->ki_loginclass, ki32->ki_loginclass, LOGINCLASSLEN + 1);
 	bcopy(ki->ki_moretdname, ki32->ki_moretdname, MAXCOMLEN - TDNAMLEN + 1);
 	CP(*ki, *ki32, ki_tracer);
 	CP(*ki, *ki32, ki_flag2);
 	CP(*ki, *ki32, ki_fibnum);
 	CP(*ki, *ki32, ki_cr_flags);
 	CP(*ki, *ki32, ki_jid);
 	CP(*ki, *ki32, ki_numthreads);
 	CP(*ki, *ki32, ki_tid);
 	CP(*ki, *ki32, ki_pri);
 	freebsd32_rusage_out(&ki->ki_rusage, &ki32->ki_rusage);
 	freebsd32_rusage_out(&ki->ki_rusage_ch, &ki32->ki_rusage_ch);
 	PTRTRIM_CP(*ki, *ki32, ki_pcb);
 	PTRTRIM_CP(*ki, *ki32, ki_kstack);
 	PTRTRIM_CP(*ki, *ki32, ki_udata);
 	PTRTRIM_CP(*ki, *ki32, ki_tdaddr);
 	CP(*ki, *ki32, ki_sflag);
 	CP(*ki, *ki32, ki_tdflags);
 }
 #endif
 
 static ssize_t
 kern_proc_out_size(struct proc *p, int flags)
 {
 	ssize_t size = 0;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 
 	if ((flags & KERN_PROC_NOTHREADS) != 0) {
 #ifdef COMPAT_FREEBSD32
 		if ((flags & KERN_PROC_MASK32) != 0) {
 			size += sizeof(struct kinfo_proc32);
 		} else
 #endif
 			size += sizeof(struct kinfo_proc);
 	} else {
 #ifdef COMPAT_FREEBSD32
 		if ((flags & KERN_PROC_MASK32) != 0)
 			size += sizeof(struct kinfo_proc32) * p->p_numthreads;
 		else
 #endif
 			size += sizeof(struct kinfo_proc) * p->p_numthreads;
 	}
 	PROC_UNLOCK(p);
 	return (size);
 }
 
 int
 kern_proc_out(struct proc *p, struct sbuf *sb, int flags)
 {
 	struct thread *td;
 	struct kinfo_proc ki;
 #ifdef COMPAT_FREEBSD32
 	struct kinfo_proc32 ki32;
 #endif
 	int error;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 	MPASS(FIRST_THREAD_IN_PROC(p) != NULL);
 
 	error = 0;
 	fill_kinfo_proc(p, &ki);
 	if ((flags & KERN_PROC_NOTHREADS) != 0) {
 #ifdef COMPAT_FREEBSD32
 		if ((flags & KERN_PROC_MASK32) != 0) {
 			freebsd32_kinfo_proc_out(&ki, &ki32);
 			if (sbuf_bcat(sb, &ki32, sizeof(ki32)) != 0)
 				error = ENOMEM;
 		} else
 #endif
 			if (sbuf_bcat(sb, &ki, sizeof(ki)) != 0)
 				error = ENOMEM;
 	} else {
 		FOREACH_THREAD_IN_PROC(p, td) {
 			fill_kinfo_thread(td, &ki, 1);
 #ifdef COMPAT_FREEBSD32
 			if ((flags & KERN_PROC_MASK32) != 0) {
 				freebsd32_kinfo_proc_out(&ki, &ki32);
 				if (sbuf_bcat(sb, &ki32, sizeof(ki32)) != 0)
 					error = ENOMEM;
 			} else
 #endif
 				if (sbuf_bcat(sb, &ki, sizeof(ki)) != 0)
 					error = ENOMEM;
 			if (error != 0)
 				break;
 		}
 	}
 	PROC_UNLOCK(p);
 	return (error);
 }
 
 static int
 sysctl_out_proc(struct proc *p, struct sysctl_req *req, int flags)
 {
 	struct sbuf sb;
 	struct kinfo_proc ki;
 	int error, error2;
 
 	if (req->oldptr == NULL)
 		return (SYSCTL_OUT(req, 0, kern_proc_out_size(p, flags)));
 
 	sbuf_new_for_sysctl(&sb, (char *)&ki, sizeof(ki), req);
 	sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
 	error = kern_proc_out(p, &sb, flags);
 	error2 = sbuf_finish(&sb);
 	sbuf_delete(&sb);
 	if (error != 0)
 		return (error);
 	else if (error2 != 0)
 		return (error2);
 	return (0);
 }
 
 int
 proc_iterate(int (*cb)(struct proc *, void *), void *cbarg)
 {
 	struct proc *p;
 	int error, i, j;
 
 	for (i = 0; i < pidhashlock + 1; i++) {
 		sx_slock(&proctree_lock);
 		sx_slock(&pidhashtbl_lock[i]);
 		for (j = i; j <= pidhash; j += pidhashlock + 1) {
 			LIST_FOREACH(p, &pidhashtbl[j], p_hash) {
 				if (p->p_state == PRS_NEW)
 					continue;
 				error = cb(p, cbarg);
 				PROC_LOCK_ASSERT(p, MA_NOTOWNED);
 				if (error != 0) {
 					sx_sunlock(&pidhashtbl_lock[i]);
 					sx_sunlock(&proctree_lock);
 					return (error);
 				}
 			}
 		}
 		sx_sunlock(&pidhashtbl_lock[i]);
 		sx_sunlock(&proctree_lock);
 	}
 	return (0);
 }
 
 struct kern_proc_out_args {
 	struct sysctl_req *req;
 	int flags;
 	int oid_number;
 	int *name;
 };
 
 static int
 sysctl_kern_proc_iterate(struct proc *p, void *origarg)
 {
 	struct kern_proc_out_args *arg = origarg;
 	int *name = arg->name;
 	int oid_number = arg->oid_number;
 	int flags = arg->flags;
 	struct sysctl_req *req = arg->req;
 	int error = 0;
 
 	PROC_LOCK(p);
 
 	KASSERT(p->p_ucred != NULL,
 	    ("process credential is NULL for non-NEW proc"));
 	/*
 	 * Show a user only appropriate processes.
 	 */
 	if (p_cansee(curthread, p))
 		goto skip;
 	/*
 	 * TODO - make more efficient (see notes below).
 	 * do by session.
 	 */
 	switch (oid_number) {
 	case KERN_PROC_GID:
 		if (p->p_ucred->cr_gid != (gid_t)name[0])
 			goto skip;
 		break;
 
 	case KERN_PROC_PGRP:
 		/* could do this by traversing pgrp */
 		if (p->p_pgrp == NULL ||
 		    p->p_pgrp->pg_id != (pid_t)name[0])
 			goto skip;
 		break;
 
 	case KERN_PROC_RGID:
 		if (p->p_ucred->cr_rgid != (gid_t)name[0])
 			goto skip;
 		break;
 
 	case KERN_PROC_SESSION:
 		if (p->p_session == NULL ||
 		    p->p_session->s_sid != (pid_t)name[0])
 			goto skip;
 		break;
 
 	case KERN_PROC_TTY:
 		if ((p->p_flag & P_CONTROLT) == 0 ||
 		    p->p_session == NULL)
 			goto skip;
 		/* XXX proctree_lock */
 		SESS_LOCK(p->p_session);
 		if (p->p_session->s_ttyp == NULL ||
 		    tty_udev(p->p_session->s_ttyp) !=
 		    (dev_t)name[0]) {
 			SESS_UNLOCK(p->p_session);
 			goto skip;
 		}
 		SESS_UNLOCK(p->p_session);
 		break;
 
 	case KERN_PROC_UID:
 		if (p->p_ucred->cr_uid != (uid_t)name[0])
 			goto skip;
 		break;
 
 	case KERN_PROC_RUID:
 		if (p->p_ucred->cr_ruid != (uid_t)name[0])
 			goto skip;
 		break;
 
 	case KERN_PROC_PROC:
 		break;
 
 	default:
 		break;
 	}
 	error = sysctl_out_proc(p, req, flags);
 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
 	return (error);
 skip:
 	PROC_UNLOCK(p);
 	return (0);
 }
 
 static int
 sysctl_kern_proc(SYSCTL_HANDLER_ARGS)
 {
 	struct kern_proc_out_args iterarg;
 	int *name = (int *)arg1;
 	u_int namelen = arg2;
 	struct proc *p;
 	int flags, oid_number;
 	int error = 0;
 
 	oid_number = oidp->oid_number;
 	if (oid_number != KERN_PROC_ALL &&
 	    (oid_number & KERN_PROC_INC_THREAD) == 0)
 		flags = KERN_PROC_NOTHREADS;
 	else {
 		flags = 0;
 		oid_number &= ~KERN_PROC_INC_THREAD;
 	}
 #ifdef COMPAT_FREEBSD32
 	if (req->flags & SCTL_MASK32)
 		flags |= KERN_PROC_MASK32;
 #endif
 	if (oid_number == KERN_PROC_PID) {
 		if (namelen != 1)
 			return (EINVAL);
 		error = sysctl_wire_old_buffer(req, 0);
 		if (error)
 			return (error);
 		sx_slock(&proctree_lock);
 		error = pget((pid_t)name[0], PGET_CANSEE, &p);
 		if (error == 0)
 			error = sysctl_out_proc(p, req, flags);
 		sx_sunlock(&proctree_lock);
 		return (error);
 	}
 
 	switch (oid_number) {
 	case KERN_PROC_ALL:
 		if (namelen != 0)
 			return (EINVAL);
 		break;
 	case KERN_PROC_PROC:
 		if (namelen != 0 && namelen != 1)
 			return (EINVAL);
 		break;
 	default:
 		if (namelen != 1)
 			return (EINVAL);
 		break;
 	}
 
 	if (req->oldptr == NULL) {
 		/* overestimate by 5 procs */
 		error = SYSCTL_OUT(req, 0, sizeof (struct kinfo_proc) * 5);
 		if (error)
 			return (error);
 	} else {
 		error = sysctl_wire_old_buffer(req, 0);
 		if (error != 0)
 			return (error);
 	}
 	iterarg.flags = flags;
 	iterarg.oid_number = oid_number;
 	iterarg.req = req;
 	iterarg.name = name;
 	error = proc_iterate(sysctl_kern_proc_iterate, &iterarg);
 	return (error);
 }
 
 struct pargs *
 pargs_alloc(int len)
 {
 	struct pargs *pa;
 
 	pa = malloc(sizeof(struct pargs) + len, M_PARGS,
 		M_WAITOK);
 	refcount_init(&pa->ar_ref, 1);
 	pa->ar_length = len;
 	return (pa);
 }
 
 static void
 pargs_free(struct pargs *pa)
 {
 
 	free(pa, M_PARGS);
 }
 
 void
 pargs_hold(struct pargs *pa)
 {
 
 	if (pa == NULL)
 		return;
 	refcount_acquire(&pa->ar_ref);
 }
 
 void
 pargs_drop(struct pargs *pa)
 {
 
 	if (pa == NULL)
 		return;
 	if (refcount_release(&pa->ar_ref))
 		pargs_free(pa);
 }
 
 static int
 proc_read_string(struct thread *td, struct proc *p, const char *sptr, char *buf,
     size_t len)
 {
 	ssize_t n;
 
 	/*
 	 * This may return a short read if the string is shorter than the chunk
 	 * and is aligned at the end of the page, and the following page is not
 	 * mapped.
 	 */
 	n = proc_readmem(td, p, (vm_offset_t)sptr, buf, len);
 	if (n <= 0)
 		return (ENOMEM);
 	return (0);
 }
 
 #define PROC_AUXV_MAX	256	/* Safety limit on auxv size. */
 
 enum proc_vector_type {
 	PROC_ARG,
 	PROC_ENV,
 	PROC_AUX,
 };
 
 #ifdef COMPAT_FREEBSD32
 static int
 get_proc_vector32(struct thread *td, struct proc *p, char ***proc_vectorp,
     size_t *vsizep, enum proc_vector_type type)
 {
 	struct freebsd32_ps_strings pss;
 	Elf32_Auxinfo aux;
 	vm_offset_t vptr, ptr;
 	uint32_t *proc_vector32;
 	char **proc_vector;
 	size_t vsize, size;
 	int i, error;
 
 	error = 0;
 	if (proc_readmem(td, p, (vm_offset_t)p->p_sysent->sv_psstrings, &pss,
 	    sizeof(pss)) != sizeof(pss))
 		return (ENOMEM);
 	switch (type) {
 	case PROC_ARG:
 		vptr = (vm_offset_t)PTRIN(pss.ps_argvstr);
 		vsize = pss.ps_nargvstr;
 		if (vsize > ARG_MAX)
 			return (ENOEXEC);
 		size = vsize * sizeof(int32_t);
 		break;
 	case PROC_ENV:
 		vptr = (vm_offset_t)PTRIN(pss.ps_envstr);
 		vsize = pss.ps_nenvstr;
 		if (vsize > ARG_MAX)
 			return (ENOEXEC);
 		size = vsize * sizeof(int32_t);
 		break;
 	case PROC_AUX:
 		vptr = (vm_offset_t)PTRIN(pss.ps_envstr) +
 		    (pss.ps_nenvstr + 1) * sizeof(int32_t);
 		if (vptr % 4 != 0)
 			return (ENOEXEC);
 		for (ptr = vptr, i = 0; i < PROC_AUXV_MAX; i++) {
 			if (proc_readmem(td, p, ptr, &aux, sizeof(aux)) !=
 			    sizeof(aux))
 				return (ENOMEM);
 			if (aux.a_type == AT_NULL)
 				break;
 			ptr += sizeof(aux);
 		}
 		if (aux.a_type != AT_NULL)
 			return (ENOEXEC);
 		vsize = i + 1;
 		size = vsize * sizeof(aux);
 		break;
 	default:
 		KASSERT(0, ("Wrong proc vector type: %d", type));
 		return (EINVAL);
 	}
 	proc_vector32 = malloc(size, M_TEMP, M_WAITOK);
 	if (proc_readmem(td, p, vptr, proc_vector32, size) != size) {
 		error = ENOMEM;
 		goto done;
 	}
 	if (type == PROC_AUX) {
 		*proc_vectorp = (char **)proc_vector32;
 		*vsizep = vsize;
 		return (0);
 	}
 	proc_vector = malloc(vsize * sizeof(char *), M_TEMP, M_WAITOK);
 	for (i = 0; i < (int)vsize; i++)
 		proc_vector[i] = PTRIN(proc_vector32[i]);
 	*proc_vectorp = proc_vector;
 	*vsizep = vsize;
 done:
 	free(proc_vector32, M_TEMP);
 	return (error);
 }
 #endif
 
 static int
 get_proc_vector(struct thread *td, struct proc *p, char ***proc_vectorp,
     size_t *vsizep, enum proc_vector_type type)
 {
 	struct ps_strings pss;
 	Elf_Auxinfo aux;
 	vm_offset_t vptr, ptr;
 	char **proc_vector;
 	size_t vsize, size;
 	int i;
 
 #ifdef COMPAT_FREEBSD32
 	if (SV_PROC_FLAG(p, SV_ILP32) != 0)
 		return (get_proc_vector32(td, p, proc_vectorp, vsizep, type));
 #endif
 	if (proc_readmem(td, p, (vm_offset_t)p->p_sysent->sv_psstrings, &pss,
 	    sizeof(pss)) != sizeof(pss))
 		return (ENOMEM);
 	switch (type) {
 	case PROC_ARG:
 		vptr = (vm_offset_t)pss.ps_argvstr;
 		vsize = pss.ps_nargvstr;
 		if (vsize > ARG_MAX)
 			return (ENOEXEC);
 		size = vsize * sizeof(char *);
 		break;
 	case PROC_ENV:
 		vptr = (vm_offset_t)pss.ps_envstr;
 		vsize = pss.ps_nenvstr;
 		if (vsize > ARG_MAX)
 			return (ENOEXEC);
 		size = vsize * sizeof(char *);
 		break;
 	case PROC_AUX:
 		/*
 		 * The aux array is just above env array on the stack. Check
 		 * that the address is naturally aligned.
 		 */
 		vptr = (vm_offset_t)pss.ps_envstr + (pss.ps_nenvstr + 1)
 		    * sizeof(char *);
 #if __ELF_WORD_SIZE == 64
 		if (vptr % sizeof(uint64_t) != 0)
 #else
 		if (vptr % sizeof(uint32_t) != 0)
 #endif
 			return (ENOEXEC);
 		/*
 		 * We count the array size reading the aux vectors from the
 		 * stack until AT_NULL vector is returned.  So (to keep the code
 		 * simple) we read the process stack twice: the first time here
 		 * to find the size and the second time when copying the vectors
 		 * to the allocated proc_vector.
 		 */
 		for (ptr = vptr, i = 0; i < PROC_AUXV_MAX; i++) {
 			if (proc_readmem(td, p, ptr, &aux, sizeof(aux)) !=
 			    sizeof(aux))
 				return (ENOMEM);
 			if (aux.a_type == AT_NULL)
 				break;
 			ptr += sizeof(aux);
 		}
 		/*
 		 * If the PROC_AUXV_MAX entries are iterated over, and we have
 		 * not reached AT_NULL, it is most likely we are reading wrong
 		 * data: either the process doesn't have auxv array or data has
 		 * been modified. Return the error in this case.
 		 */
 		if (aux.a_type != AT_NULL)
 			return (ENOEXEC);
 		vsize = i + 1;
 		size = vsize * sizeof(aux);
 		break;
 	default:
 		KASSERT(0, ("Wrong proc vector type: %d", type));
 		return (EINVAL); /* In case we are built without INVARIANTS. */
 	}
 	proc_vector = malloc(size, M_TEMP, M_WAITOK);
 	if (proc_readmem(td, p, vptr, proc_vector, size) != size) {
 		free(proc_vector, M_TEMP);
 		return (ENOMEM);
 	}
 	*proc_vectorp = proc_vector;
 	*vsizep = vsize;
 
 	return (0);
 }
 
 #define GET_PS_STRINGS_CHUNK_SZ	256	/* Chunk size (bytes) for ps_strings operations. */
 
 static int
 get_ps_strings(struct thread *td, struct proc *p, struct sbuf *sb,
     enum proc_vector_type type)
 {
 	size_t done, len, nchr, vsize;
 	int error, i;
 	char **proc_vector, *sptr;
 	char pss_string[GET_PS_STRINGS_CHUNK_SZ];
 
 	PROC_ASSERT_HELD(p);
 
 	/*
 	 * We are not going to read more than 2 * (PATH_MAX + ARG_MAX) bytes.
 	 */
 	nchr = 2 * (PATH_MAX + ARG_MAX);
 
 	error = get_proc_vector(td, p, &proc_vector, &vsize, type);
 	if (error != 0)
 		return (error);
 	for (done = 0, i = 0; i < (int)vsize && done < nchr; i++) {
 		/*
 		 * The program may have scribbled into its argv array, e.g. to
 		 * remove some arguments.  If that has happened, break out
 		 * before trying to read from NULL.
 		 */
 		if (proc_vector[i] == NULL)
 			break;
 		for (sptr = proc_vector[i]; ; sptr += GET_PS_STRINGS_CHUNK_SZ) {
 			error = proc_read_string(td, p, sptr, pss_string,
 			    sizeof(pss_string));
 			if (error != 0)
 				goto done;
 			len = strnlen(pss_string, GET_PS_STRINGS_CHUNK_SZ);
 			if (done + len >= nchr)
 				len = nchr - done - 1;
 			sbuf_bcat(sb, pss_string, len);
 			if (len != GET_PS_STRINGS_CHUNK_SZ)
 				break;
 			done += GET_PS_STRINGS_CHUNK_SZ;
 		}
 		sbuf_bcat(sb, "", 1);
 		done += len + 1;
 	}
 done:
 	free(proc_vector, M_TEMP);
 	return (error);
 }
 
 int
 proc_getargv(struct thread *td, struct proc *p, struct sbuf *sb)
 {
 
 	return (get_ps_strings(curthread, p, sb, PROC_ARG));
 }
 
 int
 proc_getenvv(struct thread *td, struct proc *p, struct sbuf *sb)
 {
 
 	return (get_ps_strings(curthread, p, sb, PROC_ENV));
 }
 
 int
 proc_getauxv(struct thread *td, struct proc *p, struct sbuf *sb)
 {
 	size_t vsize, size;
 	char **auxv;
 	int error;
 
 	error = get_proc_vector(td, p, &auxv, &vsize, PROC_AUX);
 	if (error == 0) {
 #ifdef COMPAT_FREEBSD32
 		if (SV_PROC_FLAG(p, SV_ILP32) != 0)
 			size = vsize * sizeof(Elf32_Auxinfo);
 		else
 #endif
 			size = vsize * sizeof(Elf_Auxinfo);
 		if (sbuf_bcat(sb, auxv, size) != 0)
 			error = ENOMEM;
 		free(auxv, M_TEMP);
 	}
 	return (error);
 }
 
 /*
  * This sysctl allows a process to retrieve the argument list or process
  * title for another process without groping around in the address space
  * of the other process.  It also allow a process to set its own "process 
  * title to a string of its own choice.
  */
 static int
 sysctl_kern_proc_args(SYSCTL_HANDLER_ARGS)
 {
 	int *name = (int *)arg1;
 	u_int namelen = arg2;
 	struct pargs *newpa, *pa;
 	struct proc *p;
 	struct sbuf sb;
 	int flags, error = 0, error2;
 	pid_t pid;
 
 	if (namelen != 1)
 		return (EINVAL);
 
 	p = curproc;
 	pid = (pid_t)name[0];
 	if (pid == -1) {
 		pid = p->p_pid;
 	}
 
 	/*
 	 * If the query is for this process and it is single-threaded, there
 	 * is nobody to modify pargs, thus we can just read.
 	 */
 	if (pid == p->p_pid && p->p_numthreads == 1 && req->newptr == NULL &&
 	    (pa = p->p_args) != NULL)
 		return (SYSCTL_OUT(req, pa->ar_args, pa->ar_length));
 
 	flags = PGET_CANSEE;
 	if (req->newptr != NULL)
 		flags |= PGET_ISCURRENT;
 	error = pget(pid, flags, &p);
 	if (error)
 		return (error);
 
 	pa = p->p_args;
 	if (pa != NULL) {
 		pargs_hold(pa);
 		PROC_UNLOCK(p);
 		error = SYSCTL_OUT(req, pa->ar_args, pa->ar_length);
 		pargs_drop(pa);
 	} else if ((p->p_flag & (P_WEXIT | P_SYSTEM)) == 0) {
 		_PHOLD(p);
 		PROC_UNLOCK(p);
 		sbuf_new_for_sysctl(&sb, NULL, GET_PS_STRINGS_CHUNK_SZ, req);
 		sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
 		error = proc_getargv(curthread, p, &sb);
 		error2 = sbuf_finish(&sb);
 		PRELE(p);
 		sbuf_delete(&sb);
 		if (error == 0 && error2 != 0)
 			error = error2;
 	} else {
 		PROC_UNLOCK(p);
 	}
 	if (error != 0 || req->newptr == NULL)
 		return (error);
 
 	if (req->newlen > ps_arg_cache_limit - sizeof(struct pargs))
 		return (ENOMEM);
 
 	if (req->newlen == 0) {
 		/*
 		 * Clear the argument pointer, so that we'll fetch arguments
 		 * with proc_getargv() until further notice.
 		 */
 		newpa = NULL;
 	} else {
 		newpa = pargs_alloc(req->newlen);
 		error = SYSCTL_IN(req, newpa->ar_args, req->newlen);
 		if (error != 0) {
 			pargs_free(newpa);
 			return (error);
 		}
 	}
 	PROC_LOCK(p);
 	pa = p->p_args;
 	p->p_args = newpa;
 	PROC_UNLOCK(p);
 	pargs_drop(pa);
 	return (0);
 }
 
 /*
  * This sysctl allows a process to retrieve environment of another process.
  */
 static int
 sysctl_kern_proc_env(SYSCTL_HANDLER_ARGS)
 {
 	int *name = (int *)arg1;
 	u_int namelen = arg2;
 	struct proc *p;
 	struct sbuf sb;
 	int error, error2;
 
 	if (namelen != 1)
 		return (EINVAL);
 
 	error = pget((pid_t)name[0], PGET_WANTREAD, &p);
 	if (error != 0)
 		return (error);
 	if ((p->p_flag & P_SYSTEM) != 0) {
 		PRELE(p);
 		return (0);
 	}
 
 	sbuf_new_for_sysctl(&sb, NULL, GET_PS_STRINGS_CHUNK_SZ, req);
 	sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
 	error = proc_getenvv(curthread, p, &sb);
 	error2 = sbuf_finish(&sb);
 	PRELE(p);
 	sbuf_delete(&sb);
 	return (error != 0 ? error : error2);
 }
 
 /*
  * This sysctl allows a process to retrieve ELF auxiliary vector of
  * another process.
  */
 static int
 sysctl_kern_proc_auxv(SYSCTL_HANDLER_ARGS)
 {
 	int *name = (int *)arg1;
 	u_int namelen = arg2;
 	struct proc *p;
 	struct sbuf sb;
 	int error, error2;
 
 	if (namelen != 1)
 		return (EINVAL);
 
 	error = pget((pid_t)name[0], PGET_WANTREAD, &p);
 	if (error != 0)
 		return (error);
 	if ((p->p_flag & P_SYSTEM) != 0) {
 		PRELE(p);
 		return (0);
 	}
 	sbuf_new_for_sysctl(&sb, NULL, GET_PS_STRINGS_CHUNK_SZ, req);
 	sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
 	error = proc_getauxv(curthread, p, &sb);
 	error2 = sbuf_finish(&sb);
 	PRELE(p);
 	sbuf_delete(&sb);
 	return (error != 0 ? error : error2);
 }
 
 /*
  * This sysctl allows a process to retrieve the path of the executable for
  * itself or another process.
  */
 static int
 sysctl_kern_proc_pathname(SYSCTL_HANDLER_ARGS)
 {
 	pid_t *pidp = (pid_t *)arg1;
 	unsigned int arglen = arg2;
 	struct proc *p;
 	struct vnode *vp;
 	char *retbuf, *freebuf;
 	int error;
 
 	if (arglen != 1)
 		return (EINVAL);
 	if (*pidp == -1) {	/* -1 means this process */
 		p = req->td->td_proc;
 	} else {
 		error = pget(*pidp, PGET_CANSEE, &p);
 		if (error != 0)
 			return (error);
 	}
 
 	vp = p->p_textvp;
 	if (vp == NULL) {
 		if (*pidp != -1)
 			PROC_UNLOCK(p);
 		return (0);
 	}
 	vref(vp);
 	if (*pidp != -1)
 		PROC_UNLOCK(p);
 	error = vn_fullpath(vp, &retbuf, &freebuf);
 	vrele(vp);
 	if (error)
 		return (error);
 	error = SYSCTL_OUT(req, retbuf, strlen(retbuf) + 1);
 	free(freebuf, M_TEMP);
 	return (error);
 }
 
 static int
 sysctl_kern_proc_sv_name(SYSCTL_HANDLER_ARGS)
 {
 	struct proc *p;
 	char *sv_name;
 	int *name;
 	int namelen;
 	int error;
 
 	namelen = arg2;
 	if (namelen != 1)
 		return (EINVAL);
 
 	name = (int *)arg1;
 	error = pget((pid_t)name[0], PGET_CANSEE, &p);
 	if (error != 0)
 		return (error);
 	sv_name = p->p_sysent->sv_name;
 	PROC_UNLOCK(p);
 	return (sysctl_handle_string(oidp, sv_name, 0, req));
 }
 
 #ifdef KINFO_OVMENTRY_SIZE
 CTASSERT(sizeof(struct kinfo_ovmentry) == KINFO_OVMENTRY_SIZE);
 #endif
 
 #ifdef COMPAT_FREEBSD7
 static int
 sysctl_kern_proc_ovmmap(SYSCTL_HANDLER_ARGS)
 {
 	vm_map_entry_t entry, tmp_entry;
 	unsigned int last_timestamp, namelen;
 	char *fullpath, *freepath;
 	struct kinfo_ovmentry *kve;
 	struct vattr va;
 	struct ucred *cred;
 	int error, *name;
 	struct vnode *vp;
 	struct proc *p;
 	vm_map_t map;
 	struct vmspace *vm;
 
 	namelen = arg2;
 	if (namelen != 1)
 		return (EINVAL);
 
 	name = (int *)arg1;
 	error = pget((pid_t)name[0], PGET_WANTREAD, &p);
 	if (error != 0)
 		return (error);
 	vm = vmspace_acquire_ref(p);
 	if (vm == NULL) {
 		PRELE(p);
 		return (ESRCH);
 	}
 	kve = malloc(sizeof(*kve), M_TEMP, M_WAITOK);
 
 	map = &vm->vm_map;
 	vm_map_lock_read(map);
 	VM_MAP_ENTRY_FOREACH(entry, map) {
 		vm_object_t obj, tobj, lobj;
 		vm_offset_t addr;
 
 		if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
 			continue;
 
 		bzero(kve, sizeof(*kve));
 		kve->kve_structsize = sizeof(*kve);
 
 		kve->kve_private_resident = 0;
 		obj = entry->object.vm_object;
 		if (obj != NULL) {
 			VM_OBJECT_RLOCK(obj);
 			if (obj->shadow_count == 1)
 				kve->kve_private_resident =
 				    obj->resident_page_count;
 		}
 		kve->kve_resident = 0;
 		addr = entry->start;
 		while (addr < entry->end) {
 			if (pmap_extract(map->pmap, addr))
 				kve->kve_resident++;
 			addr += PAGE_SIZE;
 		}
 
 		for (lobj = tobj = obj; tobj; tobj = tobj->backing_object) {
 			if (tobj != obj) {
 				VM_OBJECT_RLOCK(tobj);
 				kve->kve_offset += tobj->backing_object_offset;
 			}
 			if (lobj != obj)
 				VM_OBJECT_RUNLOCK(lobj);
 			lobj = tobj;
 		}
 
 		kve->kve_start = (void*)entry->start;
 		kve->kve_end = (void*)entry->end;
 		kve->kve_offset += (off_t)entry->offset;
 
 		if (entry->protection & VM_PROT_READ)
 			kve->kve_protection |= KVME_PROT_READ;
 		if (entry->protection & VM_PROT_WRITE)
 			kve->kve_protection |= KVME_PROT_WRITE;
 		if (entry->protection & VM_PROT_EXECUTE)
 			kve->kve_protection |= KVME_PROT_EXEC;
 
 		if (entry->eflags & MAP_ENTRY_COW)
 			kve->kve_flags |= KVME_FLAG_COW;
 		if (entry->eflags & MAP_ENTRY_NEEDS_COPY)
 			kve->kve_flags |= KVME_FLAG_NEEDS_COPY;
 		if (entry->eflags & MAP_ENTRY_NOCOREDUMP)
 			kve->kve_flags |= KVME_FLAG_NOCOREDUMP;
 
 		last_timestamp = map->timestamp;
 		vm_map_unlock_read(map);
 
 		kve->kve_fileid = 0;
 		kve->kve_fsid = 0;
 		freepath = NULL;
 		fullpath = "";
 		if (lobj) {
 			kve->kve_type = vm_object_kvme_type(lobj, &vp);
 			if (kve->kve_type == KVME_TYPE_MGTDEVICE)
 				kve->kve_type = KVME_TYPE_UNKNOWN;
 			if (vp != NULL)
 				vref(vp);
 			if (lobj != obj)
 				VM_OBJECT_RUNLOCK(lobj);
 
 			kve->kve_ref_count = obj->ref_count;
 			kve->kve_shadow_count = obj->shadow_count;
 			VM_OBJECT_RUNLOCK(obj);
 			if (vp != NULL) {
 				vn_fullpath(vp, &fullpath, &freepath);
 				cred = curthread->td_ucred;
 				vn_lock(vp, LK_SHARED | LK_RETRY);
 				if (VOP_GETATTR(vp, &va, cred) == 0) {
 					kve->kve_fileid = va.va_fileid;
 					/* truncate */
 					kve->kve_fsid = va.va_fsid;
 				}
 				vput(vp);
 			}
 		} else {
 			kve->kve_type = KVME_TYPE_NONE;
 			kve->kve_ref_count = 0;
 			kve->kve_shadow_count = 0;
 		}
 
 		strlcpy(kve->kve_path, fullpath, sizeof(kve->kve_path));
 		if (freepath != NULL)
 			free(freepath, M_TEMP);
 
 		error = SYSCTL_OUT(req, kve, sizeof(*kve));
 		vm_map_lock_read(map);
 		if (error)
 			break;
 		if (last_timestamp != map->timestamp) {
 			vm_map_lookup_entry(map, addr - 1, &tmp_entry);
 			entry = tmp_entry;
 		}
 	}
 	vm_map_unlock_read(map);
 	vmspace_free(vm);
 	PRELE(p);
 	free(kve, M_TEMP);
 	return (error);
 }
 #endif	/* COMPAT_FREEBSD7 */
 
 #ifdef KINFO_VMENTRY_SIZE
 CTASSERT(sizeof(struct kinfo_vmentry) == KINFO_VMENTRY_SIZE);
 #endif
 
 void
 kern_proc_vmmap_resident(vm_map_t map, vm_map_entry_t entry,
     int *resident_count, bool *super)
 {
 	vm_object_t obj, tobj;
 	vm_page_t m, m_adv;
 	vm_offset_t addr;
 	vm_paddr_t pa;
 	vm_pindex_t pi, pi_adv, pindex;
 
 	*super = false;
 	*resident_count = 0;
 	if (vmmap_skip_res_cnt)
 		return;
 
 	pa = 0;
 	obj = entry->object.vm_object;
 	addr = entry->start;
 	m_adv = NULL;
 	pi = OFF_TO_IDX(entry->offset);
 	for (; addr < entry->end; addr += IDX_TO_OFF(pi_adv), pi += pi_adv) {
 		if (m_adv != NULL) {
 			m = m_adv;
 		} else {
 			pi_adv = atop(entry->end - addr);
 			pindex = pi;
 			for (tobj = obj;; tobj = tobj->backing_object) {
 				m = vm_page_find_least(tobj, pindex);
 				if (m != NULL) {
 					if (m->pindex == pindex)
 						break;
 					if (pi_adv > m->pindex - pindex) {
 						pi_adv = m->pindex - pindex;
 						m_adv = m;
 					}
 				}
 				if (tobj->backing_object == NULL)
 					goto next;
 				pindex += OFF_TO_IDX(tobj->
 				    backing_object_offset);
 			}
 		}
 		m_adv = NULL;
 		if (m->psind != 0 && addr + pagesizes[1] <= entry->end &&
 		    (addr & (pagesizes[1] - 1)) == 0 &&
 		    (pmap_mincore(map->pmap, addr, &pa) & MINCORE_SUPER) != 0) {
 			*super = true;
 			pi_adv = atop(pagesizes[1]);
 		} else {
 			/*
 			 * We do not test the found page on validity.
 			 * Either the page is busy and being paged in,
 			 * or it was invalidated.  The first case
 			 * should be counted as resident, the second
 			 * is not so clear; we do account both.
 			 */
 			pi_adv = 1;
 		}
 		*resident_count += pi_adv;
 next:;
 	}
 }
 
 /*
  * Must be called with the process locked and will return unlocked.
  */
 int
 kern_proc_vmmap_out(struct proc *p, struct sbuf *sb, ssize_t maxlen, int flags)
 {
 	vm_map_entry_t entry, tmp_entry;
 	struct vattr va;
 	vm_map_t map;
 	vm_object_t lobj, nobj, obj, tobj;
 	char *fullpath, *freepath;
 	struct kinfo_vmentry *kve;
 	struct ucred *cred;
 	struct vnode *vp;
 	struct vmspace *vm;
 	vm_offset_t addr;
 	unsigned int last_timestamp;
 	int error;
 	bool guard, super;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 
 	_PHOLD(p);
 	PROC_UNLOCK(p);
 	vm = vmspace_acquire_ref(p);
 	if (vm == NULL) {
 		PRELE(p);
 		return (ESRCH);
 	}
 	kve = malloc(sizeof(*kve), M_TEMP, M_WAITOK | M_ZERO);
 
 	error = 0;
 	map = &vm->vm_map;
 	vm_map_lock_read(map);
 	VM_MAP_ENTRY_FOREACH(entry, map) {
 		if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
 			continue;
 
 		addr = entry->end;
 		bzero(kve, sizeof(*kve));
 		obj = entry->object.vm_object;
 		if (obj != NULL) {
 			if ((obj->flags & OBJ_ANON) != 0)
 				kve->kve_obj = (uintptr_t)obj;
 
 			for (tobj = obj; tobj != NULL;
 			    tobj = tobj->backing_object) {
 				VM_OBJECT_RLOCK(tobj);
 				kve->kve_offset += tobj->backing_object_offset;
 				lobj = tobj;
 			}
 			if (obj->backing_object == NULL)
 				kve->kve_private_resident =
 				    obj->resident_page_count;
 			kern_proc_vmmap_resident(map, entry,
 			    &kve->kve_resident, &super);
 			if (super)
 				kve->kve_flags |= KVME_FLAG_SUPER;
 			for (tobj = obj; tobj != NULL; tobj = nobj) {
 				nobj = tobj->backing_object;
 				if (tobj != obj && tobj != lobj)
 					VM_OBJECT_RUNLOCK(tobj);
 			}
 		} else {
 			lobj = NULL;
 		}
 
 		kve->kve_start = entry->start;
 		kve->kve_end = entry->end;
 		kve->kve_offset += entry->offset;
 
 		if (entry->protection & VM_PROT_READ)
 			kve->kve_protection |= KVME_PROT_READ;
 		if (entry->protection & VM_PROT_WRITE)
 			kve->kve_protection |= KVME_PROT_WRITE;
 		if (entry->protection & VM_PROT_EXECUTE)
 			kve->kve_protection |= KVME_PROT_EXEC;
 
 		if (entry->eflags & MAP_ENTRY_COW)
 			kve->kve_flags |= KVME_FLAG_COW;
 		if (entry->eflags & MAP_ENTRY_NEEDS_COPY)
 			kve->kve_flags |= KVME_FLAG_NEEDS_COPY;
 		if (entry->eflags & MAP_ENTRY_NOCOREDUMP)
 			kve->kve_flags |= KVME_FLAG_NOCOREDUMP;
 		if (entry->eflags & MAP_ENTRY_GROWS_UP)
 			kve->kve_flags |= KVME_FLAG_GROWS_UP;
 		if (entry->eflags & MAP_ENTRY_GROWS_DOWN)
 			kve->kve_flags |= KVME_FLAG_GROWS_DOWN;
 		if (entry->eflags & MAP_ENTRY_USER_WIRED)
 			kve->kve_flags |= KVME_FLAG_USER_WIRED;
 
 		guard = (entry->eflags & MAP_ENTRY_GUARD) != 0;
 
 		last_timestamp = map->timestamp;
 		vm_map_unlock_read(map);
 
 		freepath = NULL;
 		fullpath = "";
 		if (lobj != NULL) {
 			kve->kve_type = vm_object_kvme_type(lobj, &vp);
 			if (vp != NULL)
 				vref(vp);
 			if (lobj != obj)
 				VM_OBJECT_RUNLOCK(lobj);
 
 			kve->kve_ref_count = obj->ref_count;
 			kve->kve_shadow_count = obj->shadow_count;
 			VM_OBJECT_RUNLOCK(obj);
 			if (vp != NULL) {
 				vn_fullpath(vp, &fullpath, &freepath);
 				kve->kve_vn_type = vntype_to_kinfo(vp->v_type);
 				cred = curthread->td_ucred;
 				vn_lock(vp, LK_SHARED | LK_RETRY);
 				if (VOP_GETATTR(vp, &va, cred) == 0) {
 					kve->kve_vn_fileid = va.va_fileid;
 					kve->kve_vn_fsid = va.va_fsid;
 					kve->kve_vn_fsid_freebsd11 =
 					    kve->kve_vn_fsid; /* truncate */
 					kve->kve_vn_mode =
 					    MAKEIMODE(va.va_type, va.va_mode);
 					kve->kve_vn_size = va.va_size;
 					kve->kve_vn_rdev = va.va_rdev;
 					kve->kve_vn_rdev_freebsd11 =
 					    kve->kve_vn_rdev; /* truncate */
 					kve->kve_status = KF_ATTR_VALID;
 				}
 				vput(vp);
 			}
 		} else {
 			kve->kve_type = guard ? KVME_TYPE_GUARD :
 			    KVME_TYPE_NONE;
 			kve->kve_ref_count = 0;
 			kve->kve_shadow_count = 0;
 		}
 
 		strlcpy(kve->kve_path, fullpath, sizeof(kve->kve_path));
 		if (freepath != NULL)
 			free(freepath, M_TEMP);
 
 		/* Pack record size down */
 		if ((flags & KERN_VMMAP_PACK_KINFO) != 0)
 			kve->kve_structsize =
 			    offsetof(struct kinfo_vmentry, kve_path) +
 			    strlen(kve->kve_path) + 1;
 		else
 			kve->kve_structsize = sizeof(*kve);
 		kve->kve_structsize = roundup(kve->kve_structsize,
 		    sizeof(uint64_t));
 
 		/* Halt filling and truncate rather than exceeding maxlen */
 		if (maxlen != -1 && maxlen < kve->kve_structsize) {
 			error = 0;
 			vm_map_lock_read(map);
 			break;
 		} else if (maxlen != -1)
 			maxlen -= kve->kve_structsize;
 
 		if (sbuf_bcat(sb, kve, kve->kve_structsize) != 0)
 			error = ENOMEM;
 		vm_map_lock_read(map);
 		if (error != 0)
 			break;
 		if (last_timestamp != map->timestamp) {
 			vm_map_lookup_entry(map, addr - 1, &tmp_entry);
 			entry = tmp_entry;
 		}
 	}
 	vm_map_unlock_read(map);
 	vmspace_free(vm);
 	PRELE(p);
 	free(kve, M_TEMP);
 	return (error);
 }
 
 static int
 sysctl_kern_proc_vmmap(SYSCTL_HANDLER_ARGS)
 {
 	struct proc *p;
 	struct sbuf sb;
 	u_int namelen;
 	int error, error2, *name;
 
 	namelen = arg2;
 	if (namelen != 1)
 		return (EINVAL);
 
 	name = (int *)arg1;
 	sbuf_new_for_sysctl(&sb, NULL, sizeof(struct kinfo_vmentry), req);
 	sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
 	error = pget((pid_t)name[0], PGET_CANDEBUG | PGET_NOTWEXIT, &p);
 	if (error != 0) {
 		sbuf_delete(&sb);
 		return (error);
 	}
 	error = kern_proc_vmmap_out(p, &sb, -1, KERN_VMMAP_PACK_KINFO);
 	error2 = sbuf_finish(&sb);
 	sbuf_delete(&sb);
 	return (error != 0 ? error : error2);
 }
 
 #if defined(STACK) || defined(DDB)
 static int
 sysctl_kern_proc_kstack(SYSCTL_HANDLER_ARGS)
 {
 	struct kinfo_kstack *kkstp;
 	int error, i, *name, numthreads;
 	lwpid_t *lwpidarray;
 	struct thread *td;
 	struct stack *st;
 	struct sbuf sb;
 	struct proc *p;
 	u_int namelen;
 
 	namelen = arg2;
 	if (namelen != 1)
 		return (EINVAL);
 
 	name = (int *)arg1;
 	error = pget((pid_t)name[0], PGET_NOTINEXEC | PGET_WANTREAD, &p);
 	if (error != 0)
 		return (error);
 
 	kkstp = malloc(sizeof(*kkstp), M_TEMP, M_WAITOK);
 	st = stack_create(M_WAITOK);
 
 	lwpidarray = NULL;
 	PROC_LOCK(p);
 	do {
 		if (lwpidarray != NULL) {
 			free(lwpidarray, M_TEMP);
 			lwpidarray = NULL;
 		}
 		numthreads = p->p_numthreads;
 		PROC_UNLOCK(p);
 		lwpidarray = malloc(sizeof(*lwpidarray) * numthreads, M_TEMP,
 		    M_WAITOK | M_ZERO);
 		PROC_LOCK(p);
 	} while (numthreads < p->p_numthreads);
 
 	/*
 	 * XXXRW: During the below loop, execve(2) and countless other sorts
 	 * of changes could have taken place.  Should we check to see if the
 	 * vmspace has been replaced, or the like, in order to prevent
 	 * giving a snapshot that spans, say, execve(2), with some threads
 	 * before and some after?  Among other things, the credentials could
 	 * have changed, in which case the right to extract debug info might
 	 * no longer be assured.
 	 */
 	i = 0;
 	FOREACH_THREAD_IN_PROC(p, td) {
 		KASSERT(i < numthreads,
 		    ("sysctl_kern_proc_kstack: numthreads"));
 		lwpidarray[i] = td->td_tid;
 		i++;
 	}
 	PROC_UNLOCK(p);
 	numthreads = i;
 	for (i = 0; i < numthreads; i++) {
 		td = tdfind(lwpidarray[i], p->p_pid);
 		if (td == NULL) {
 			continue;
 		}
 		bzero(kkstp, sizeof(*kkstp));
 		(void)sbuf_new(&sb, kkstp->kkst_trace,
 		    sizeof(kkstp->kkst_trace), SBUF_FIXEDLEN);
 		thread_lock(td);
 		kkstp->kkst_tid = td->td_tid;
 		if (TD_IS_SWAPPED(td))
 			kkstp->kkst_state = KKST_STATE_SWAPPED;
 		else if (stack_save_td(st, td) == 0)
 			kkstp->kkst_state = KKST_STATE_STACKOK;
 		else
 			kkstp->kkst_state = KKST_STATE_RUNNING;
 		thread_unlock(td);
 		PROC_UNLOCK(p);
 		stack_sbuf_print(&sb, st);
 		sbuf_finish(&sb);
 		sbuf_delete(&sb);
 		error = SYSCTL_OUT(req, kkstp, sizeof(*kkstp));
 		if (error)
 			break;
 	}
 	PRELE(p);
 	if (lwpidarray != NULL)
 		free(lwpidarray, M_TEMP);
 	stack_destroy(st);
 	free(kkstp, M_TEMP);
 	return (error);
 }
 #endif
 
 /*
  * This sysctl allows a process to retrieve the full list of groups from
  * itself or another process.
  */
 static int
 sysctl_kern_proc_groups(SYSCTL_HANDLER_ARGS)
 {
 	pid_t *pidp = (pid_t *)arg1;
 	unsigned int arglen = arg2;
 	struct proc *p;
 	struct ucred *cred;
 	int error;
 
 	if (arglen != 1)
 		return (EINVAL);
 	if (*pidp == -1) {	/* -1 means this process */
 		p = req->td->td_proc;
 		PROC_LOCK(p);
 	} else {
 		error = pget(*pidp, PGET_CANSEE, &p);
 		if (error != 0)
 			return (error);
 	}
 
 	cred = crhold(p->p_ucred);
 	PROC_UNLOCK(p);
 
 	error = SYSCTL_OUT(req, cred->cr_groups,
 	    cred->cr_ngroups * sizeof(gid_t));
 	crfree(cred);
 	return (error);
 }
 
 /*
  * This sysctl allows a process to retrieve or/and set the resource limit for
  * another process.
  */
 static int
 sysctl_kern_proc_rlimit(SYSCTL_HANDLER_ARGS)
 {
 	int *name = (int *)arg1;
 	u_int namelen = arg2;
 	struct rlimit rlim;
 	struct proc *p;
 	u_int which;
 	int flags, error;
 
 	if (namelen != 2)
 		return (EINVAL);
 
 	which = (u_int)name[1];
 	if (which >= RLIM_NLIMITS)
 		return (EINVAL);
 
 	if (req->newptr != NULL && req->newlen != sizeof(rlim))
 		return (EINVAL);
 
 	flags = PGET_HOLD | PGET_NOTWEXIT;
 	if (req->newptr != NULL)
 		flags |= PGET_CANDEBUG;
 	else
 		flags |= PGET_CANSEE;
 	error = pget((pid_t)name[0], flags, &p);
 	if (error != 0)
 		return (error);
 
 	/*
 	 * Retrieve limit.
 	 */
 	if (req->oldptr != NULL) {
 		PROC_LOCK(p);
 		lim_rlimit_proc(p, which, &rlim);
 		PROC_UNLOCK(p);
 	}
 	error = SYSCTL_OUT(req, &rlim, sizeof(rlim));
 	if (error != 0)
 		goto errout;
 
 	/*
 	 * Set limit.
 	 */
 	if (req->newptr != NULL) {
 		error = SYSCTL_IN(req, &rlim, sizeof(rlim));
 		if (error == 0)
 			error = kern_proc_setrlimit(curthread, p, which, &rlim);
 	}
 
 errout:
 	PRELE(p);
 	return (error);
 }
 
 /*
  * This sysctl allows a process to retrieve ps_strings structure location of
  * another process.
  */
 static int
 sysctl_kern_proc_ps_strings(SYSCTL_HANDLER_ARGS)
 {
 	int *name = (int *)arg1;
 	u_int namelen = arg2;
 	struct proc *p;
 	vm_offset_t ps_strings;
 	int error;
 #ifdef COMPAT_FREEBSD32
 	uint32_t ps_strings32;
 #endif
 
 	if (namelen != 1)
 		return (EINVAL);
 
 	error = pget((pid_t)name[0], PGET_CANDEBUG, &p);
 	if (error != 0)
 		return (error);
 #ifdef COMPAT_FREEBSD32
 	if ((req->flags & SCTL_MASK32) != 0) {
 		/*
 		 * We return 0 if the 32 bit emulation request is for a 64 bit
 		 * process.
 		 */
 		ps_strings32 = SV_PROC_FLAG(p, SV_ILP32) != 0 ?
 		    PTROUT(p->p_sysent->sv_psstrings) : 0;
 		PROC_UNLOCK(p);
 		error = SYSCTL_OUT(req, &ps_strings32, sizeof(ps_strings32));
 		return (error);
 	}
 #endif
 	ps_strings = p->p_sysent->sv_psstrings;
 	PROC_UNLOCK(p);
 	error = SYSCTL_OUT(req, &ps_strings, sizeof(ps_strings));
 	return (error);
 }
 
 /*
  * This sysctl allows a process to retrieve umask of another process.
  */
 static int
 sysctl_kern_proc_umask(SYSCTL_HANDLER_ARGS)
 {
 	int *name = (int *)arg1;
 	u_int namelen = arg2;
 	struct proc *p;
 	int error;
 	u_short cmask;
 	pid_t pid;
 
 	if (namelen != 1)
 		return (EINVAL);
 
 	pid = (pid_t)name[0];
 	p = curproc;
 	if (pid == p->p_pid || pid == 0) {
 		cmask = p->p_pd->pd_cmask;
 		goto out;
 	}
 
 	error = pget(pid, PGET_WANTREAD, &p);
 	if (error != 0)
 		return (error);
 
 	cmask = p->p_pd->pd_cmask;
 	PRELE(p);
 out:
 	error = SYSCTL_OUT(req, &cmask, sizeof(cmask));
 	return (error);
 }
 
 /*
  * This sysctl allows a process to set and retrieve binary osreldate of
  * another process.
  */
 static int
 sysctl_kern_proc_osrel(SYSCTL_HANDLER_ARGS)
 {
 	int *name = (int *)arg1;
 	u_int namelen = arg2;
 	struct proc *p;
 	int flags, error, osrel;
 
 	if (namelen != 1)
 		return (EINVAL);
 
 	if (req->newptr != NULL && req->newlen != sizeof(osrel))
 		return (EINVAL);
 
 	flags = PGET_HOLD | PGET_NOTWEXIT;
 	if (req->newptr != NULL)
 		flags |= PGET_CANDEBUG;
 	else
 		flags |= PGET_CANSEE;
 	error = pget((pid_t)name[0], flags, &p);
 	if (error != 0)
 		return (error);
 
 	error = SYSCTL_OUT(req, &p->p_osrel, sizeof(p->p_osrel));
 	if (error != 0)
 		goto errout;
 
 	if (req->newptr != NULL) {
 		error = SYSCTL_IN(req, &osrel, sizeof(osrel));
 		if (error != 0)
 			goto errout;
 		if (osrel < 0) {
 			error = EINVAL;
 			goto errout;
 		}
 		p->p_osrel = osrel;
 	}
 errout:
 	PRELE(p);
 	return (error);
 }
 
 static int
 sysctl_kern_proc_sigtramp(SYSCTL_HANDLER_ARGS)
 {
 	int *name = (int *)arg1;
 	u_int namelen = arg2;
 	struct proc *p;
 	struct kinfo_sigtramp kst;
 	const struct sysentvec *sv;
 	int error;
 #ifdef COMPAT_FREEBSD32
 	struct kinfo_sigtramp32 kst32;
 #endif
 
 	if (namelen != 1)
 		return (EINVAL);
 
 	error = pget((pid_t)name[0], PGET_CANDEBUG, &p);
 	if (error != 0)
 		return (error);
 	sv = p->p_sysent;
 #ifdef COMPAT_FREEBSD32
 	if ((req->flags & SCTL_MASK32) != 0) {
 		bzero(&kst32, sizeof(kst32));
 		if (SV_PROC_FLAG(p, SV_ILP32)) {
 			if (sv->sv_sigcode_base != 0) {
 				kst32.ksigtramp_start = sv->sv_sigcode_base;
 				kst32.ksigtramp_end = sv->sv_sigcode_base +
 				    *sv->sv_szsigcode;
 			} else {
 				kst32.ksigtramp_start = sv->sv_psstrings -
 				    *sv->sv_szsigcode;
 				kst32.ksigtramp_end = sv->sv_psstrings;
 			}
 		}
 		PROC_UNLOCK(p);
 		error = SYSCTL_OUT(req, &kst32, sizeof(kst32));
 		return (error);
 	}
 #endif
 	bzero(&kst, sizeof(kst));
 	if (sv->sv_sigcode_base != 0) {
 		kst.ksigtramp_start = (char *)sv->sv_sigcode_base;
 		kst.ksigtramp_end = (char *)sv->sv_sigcode_base +
 		    *sv->sv_szsigcode;
 	} else {
 		kst.ksigtramp_start = (char *)sv->sv_psstrings -
 		    *sv->sv_szsigcode;
 		kst.ksigtramp_end = (char *)sv->sv_psstrings;
 	}
 	PROC_UNLOCK(p);
 	error = SYSCTL_OUT(req, &kst, sizeof(kst));
 	return (error);
 }
 
 static int
 sysctl_kern_proc_sigfastblk(SYSCTL_HANDLER_ARGS)
 {
 	int *name = (int *)arg1;
 	u_int namelen = arg2;
 	pid_t pid;
 	struct proc *p;
 	struct thread *td1;
 	uintptr_t addr;
 #ifdef COMPAT_FREEBSD32
 	uint32_t addr32;
 #endif
 	int error;
 
 	if (namelen != 1 || req->newptr != NULL)
 		return (EINVAL);
 
 	pid = (pid_t)name[0];
 	error = pget(pid, PGET_HOLD | PGET_NOTWEXIT | PGET_CANDEBUG, &p);
 	if (error != 0)
 		return (error);
 
 	PROC_LOCK(p);
 #ifdef COMPAT_FREEBSD32
 	if (SV_CURPROC_FLAG(SV_ILP32)) {
 		if (!SV_PROC_FLAG(p, SV_ILP32)) {
 			error = EINVAL;
 			goto errlocked;
 		}
 	}
 #endif
 	if (pid <= PID_MAX) {
 		td1 = FIRST_THREAD_IN_PROC(p);
 	} else {
 		FOREACH_THREAD_IN_PROC(p, td1) {
 			if (td1->td_tid == pid)
 				break;
 		}
 	}
 	if (td1 == NULL) {
 		error = ESRCH;
 		goto errlocked;
 	}
 	/*
 	 * The access to the private thread flags.  It is fine as far
 	 * as no out-of-thin-air values are read from td_pflags, and
 	 * usermode read of the td_sigblock_ptr is racy inherently,
 	 * since target process might have already changed it
 	 * meantime.
 	 */
 	if ((td1->td_pflags & TDP_SIGFASTBLOCK) != 0)
 		addr = (uintptr_t)td1->td_sigblock_ptr;
 	else
 		error = ENOTTY;
 
 errlocked:
 	_PRELE(p);
 	PROC_UNLOCK(p);
 	if (error != 0)
 		return (error);
 
 #ifdef COMPAT_FREEBSD32
 	if (SV_CURPROC_FLAG(SV_ILP32)) {
 		addr32 = addr;
 		error = SYSCTL_OUT(req, &addr32, sizeof(addr32));
 	} else
 #endif
 		error = SYSCTL_OUT(req, &addr, sizeof(addr));
 	return (error);
 }
 
 SYSCTL_NODE(_kern, KERN_PROC, proc, CTLFLAG_RD | CTLFLAG_MPSAFE,  0,
     "Process table");
 
 SYSCTL_PROC(_kern_proc, KERN_PROC_ALL, all, CTLFLAG_RD|CTLTYPE_STRUCT|
 	CTLFLAG_MPSAFE, 0, 0, sysctl_kern_proc, "S,proc",
 	"Return entire process table");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_GID, gid, CTLFLAG_RD | CTLFLAG_MPSAFE,
 	sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_PGRP, pgrp, CTLFLAG_RD | CTLFLAG_MPSAFE,
 	sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_RGID, rgid, CTLFLAG_RD | CTLFLAG_MPSAFE,
 	sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_SESSION, sid, CTLFLAG_RD |
 	CTLFLAG_MPSAFE, sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_TTY, tty, CTLFLAG_RD | CTLFLAG_MPSAFE,
 	sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_UID, uid, CTLFLAG_RD | CTLFLAG_MPSAFE,
 	sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_RUID, ruid, CTLFLAG_RD | CTLFLAG_MPSAFE,
 	sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_PID, pid, CTLFLAG_RD | CTLFLAG_MPSAFE,
 	sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_PROC, proc, CTLFLAG_RD | CTLFLAG_MPSAFE,
 	sysctl_kern_proc, "Return process table, no threads");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_ARGS, args,
 	CTLFLAG_RW | CTLFLAG_CAPWR | CTLFLAG_ANYBODY | CTLFLAG_MPSAFE,
 	sysctl_kern_proc_args, "Process argument list");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_ENV, env, CTLFLAG_RD | CTLFLAG_MPSAFE,
 	sysctl_kern_proc_env, "Process environment");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_AUXV, auxv, CTLFLAG_RD |
 	CTLFLAG_MPSAFE, sysctl_kern_proc_auxv, "Process ELF auxiliary vector");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_PATHNAME, pathname, CTLFLAG_RD |
 	CTLFLAG_MPSAFE, sysctl_kern_proc_pathname, "Process executable path");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_SV_NAME, sv_name, CTLFLAG_RD |
 	CTLFLAG_MPSAFE, sysctl_kern_proc_sv_name,
 	"Process syscall vector name (ABI type)");
 
 static SYSCTL_NODE(_kern_proc, (KERN_PROC_GID | KERN_PROC_INC_THREAD), gid_td,
 	CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, (KERN_PROC_PGRP | KERN_PROC_INC_THREAD), pgrp_td,
 	CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, (KERN_PROC_RGID | KERN_PROC_INC_THREAD), rgid_td,
 	CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, (KERN_PROC_SESSION | KERN_PROC_INC_THREAD),
 	sid_td, CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, (KERN_PROC_TTY | KERN_PROC_INC_THREAD), tty_td,
 	CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, (KERN_PROC_UID | KERN_PROC_INC_THREAD), uid_td,
 	CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, (KERN_PROC_RUID | KERN_PROC_INC_THREAD), ruid_td,
 	CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, (KERN_PROC_PID | KERN_PROC_INC_THREAD), pid_td,
 	CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_kern_proc, "Process table");
 
 static SYSCTL_NODE(_kern_proc, (KERN_PROC_PROC | KERN_PROC_INC_THREAD), proc_td,
 	CTLFLAG_RD | CTLFLAG_MPSAFE, sysctl_kern_proc,
 	"Return process table, including threads");
 
 #ifdef COMPAT_FREEBSD7
 static SYSCTL_NODE(_kern_proc, KERN_PROC_OVMMAP, ovmmap, CTLFLAG_RD |
 	CTLFLAG_MPSAFE, sysctl_kern_proc_ovmmap, "Old Process vm map entries");
 #endif
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_VMMAP, vmmap, CTLFLAG_RD |
 	CTLFLAG_MPSAFE, sysctl_kern_proc_vmmap, "Process vm map entries");
 
 #if defined(STACK) || defined(DDB)
 static SYSCTL_NODE(_kern_proc, KERN_PROC_KSTACK, kstack, CTLFLAG_RD |
 	CTLFLAG_MPSAFE, sysctl_kern_proc_kstack, "Process kernel stacks");
 #endif
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_GROUPS, groups, CTLFLAG_RD |
 	CTLFLAG_MPSAFE, sysctl_kern_proc_groups, "Process groups");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_RLIMIT, rlimit, CTLFLAG_RW |
 	CTLFLAG_ANYBODY | CTLFLAG_MPSAFE, sysctl_kern_proc_rlimit,
 	"Process resource limits");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_PS_STRINGS, ps_strings, CTLFLAG_RD |
 	CTLFLAG_MPSAFE, sysctl_kern_proc_ps_strings,
 	"Process ps_strings location");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_UMASK, umask, CTLFLAG_RD |
 	CTLFLAG_MPSAFE, sysctl_kern_proc_umask, "Process umask");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_OSREL, osrel, CTLFLAG_RW |
 	CTLFLAG_ANYBODY | CTLFLAG_MPSAFE, sysctl_kern_proc_osrel,
 	"Process binary osreldate");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_SIGTRAMP, sigtramp, CTLFLAG_RD |
 	CTLFLAG_MPSAFE, sysctl_kern_proc_sigtramp,
 	"Process signal trampoline location");
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_SIGFASTBLK, sigfastblk, CTLFLAG_RD |
 	CTLFLAG_ANYBODY | CTLFLAG_MPSAFE, sysctl_kern_proc_sigfastblk,
 	"Thread sigfastblock address");
 
 int allproc_gen;
 
 /*
  * stop_all_proc() purpose is to stop all process which have usermode,
  * except current process for obvious reasons.  This makes it somewhat
  * unreliable when invoked from multithreaded process.  The service
  * must not be user-callable anyway.
  */
 void
 stop_all_proc(void)
 {
 	struct proc *cp, *p;
 	int r, gen;
 	bool restart, seen_stopped, seen_exiting, stopped_some;
 
 	cp = curproc;
 allproc_loop:
 	sx_xlock(&allproc_lock);
 	gen = allproc_gen;
 	seen_exiting = seen_stopped = stopped_some = restart = false;
 	LIST_REMOVE(cp, p_list);
 	LIST_INSERT_HEAD(&allproc, cp, p_list);
 	for (;;) {
 		p = LIST_NEXT(cp, p_list);
 		if (p == NULL)
 			break;
 		LIST_REMOVE(cp, p_list);
 		LIST_INSERT_AFTER(p, cp, p_list);
 		PROC_LOCK(p);
 		if ((p->p_flag & (P_KPROC | P_SYSTEM | P_TOTAL_STOP)) != 0) {
 			PROC_UNLOCK(p);
 			continue;
 		}
 		if ((p->p_flag & P_WEXIT) != 0) {
 			seen_exiting = true;
 			PROC_UNLOCK(p);
 			continue;
 		}
 		if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
 			/*
 			 * Stopped processes are tolerated when there
 			 * are no other processes which might continue
 			 * them.  P_STOPPED_SINGLE but not
 			 * P_TOTAL_STOP process still has at least one
 			 * thread running.
 			 */
 			seen_stopped = true;
 			PROC_UNLOCK(p);
 			continue;
 		}
 		sx_xunlock(&allproc_lock);
 		_PHOLD(p);
 		r = thread_single(p, SINGLE_ALLPROC);
 		if (r != 0)
 			restart = true;
 		else
 			stopped_some = true;
 		_PRELE(p);
 		PROC_UNLOCK(p);
 		sx_xlock(&allproc_lock);
 	}
 	/* Catch forked children we did not see in iteration. */
 	if (gen != allproc_gen)
 		restart = true;
 	sx_xunlock(&allproc_lock);
 	if (restart || stopped_some || seen_exiting || seen_stopped) {
 		kern_yield(PRI_USER);
 		goto allproc_loop;
 	}
 }
 
 void
 resume_all_proc(void)
 {
 	struct proc *cp, *p;
 
 	cp = curproc;
 	sx_xlock(&allproc_lock);
 again:
 	LIST_REMOVE(cp, p_list);
 	LIST_INSERT_HEAD(&allproc, cp, p_list);
 	for (;;) {
 		p = LIST_NEXT(cp, p_list);
 		if (p == NULL)
 			break;
 		LIST_REMOVE(cp, p_list);
 		LIST_INSERT_AFTER(p, cp, p_list);
 		PROC_LOCK(p);
 		if ((p->p_flag & P_TOTAL_STOP) != 0) {
 			sx_xunlock(&allproc_lock);
 			_PHOLD(p);
 			thread_single_end(p, SINGLE_ALLPROC);
 			_PRELE(p);
 			PROC_UNLOCK(p);
 			sx_xlock(&allproc_lock);
 		} else {
 			PROC_UNLOCK(p);
 		}
 	}
 	/*  Did the loop above missed any stopped process ? */
 	FOREACH_PROC_IN_SYSTEM(p) {
 		/* No need for proc lock. */
 		if ((p->p_flag & P_TOTAL_STOP) != 0)
 			goto again;
 	}
 	sx_xunlock(&allproc_lock);
 }
 
 /* #define	TOTAL_STOP_DEBUG	1 */
 #ifdef TOTAL_STOP_DEBUG
 volatile static int ap_resume;
 #include <sys/mount.h>
 
 static int
 sysctl_debug_stop_all_proc(SYSCTL_HANDLER_ARGS)
 {
 	int error, val;
 
 	val = 0;
 	ap_resume = 0;
 	error = sysctl_handle_int(oidp, &val, 0, req);
 	if (error != 0 || req->newptr == NULL)
 		return (error);
 	if (val != 0) {
 		stop_all_proc();
 		syncer_suspend();
 		while (ap_resume == 0)
 			;
 		syncer_resume();
 		resume_all_proc();
 	}
 	return (0);
 }
 
 SYSCTL_PROC(_debug, OID_AUTO, stop_all_proc, CTLTYPE_INT | CTLFLAG_RW |
     CTLFLAG_MPSAFE, __DEVOLATILE(int *, &ap_resume), 0,
     sysctl_debug_stop_all_proc, "I",
     "");
 #endif
diff --git a/sys/kern/subr_kdb.c b/sys/kern/subr_kdb.c
index 1fabb4044eb1..4f439ff103d7 100644
--- a/sys/kern/subr_kdb.c
+++ b/sys/kern/subr_kdb.c
@@ -1,751 +1,757 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
  *
  * 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 <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include "opt_kdb.h"
 #include "opt_stack.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/cons.h>
 #include <sys/kdb.h>
 #include <sys/kernel.h>
 #include <sys/malloc.h>
 #include <sys/lock.h>
 #include <sys/pcpu.h>
 #include <sys/proc.h>
 #include <sys/sbuf.h>
 #include <sys/smp.h>
 #include <sys/stack.h>
 #include <sys/sysctl.h>
 
 #include <machine/kdb.h>
 #include <machine/pcb.h>
 
 #ifdef SMP
 #include <machine/smp.h>
 #endif
 
 u_char __read_frequently 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, NULL);
 
 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_panic_str(SYSCTL_HANDLER_ARGS);
 static int kdb_sysctl_trap(SYSCTL_HANDLER_ARGS);
 static int kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS);
 static int kdb_sysctl_stack_overflow(SYSCTL_HANDLER_ARGS);
 
 static SYSCTL_NODE(_debug, OID_AUTO, kdb, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
     "KDB nodes");
 
 SYSCTL_PROC(_debug_kdb, OID_AUTO, available,
     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
     kdb_sysctl_available, "A",
     "list of available KDB backends");
 
 SYSCTL_PROC(_debug_kdb, OID_AUTO, current,
     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0,
     kdb_sysctl_current, "A",
     "currently selected KDB backend");
 
 SYSCTL_PROC(_debug_kdb, OID_AUTO, enter,
     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
     kdb_sysctl_enter, "I",
     "set to enter the debugger");
 
 SYSCTL_PROC(_debug_kdb, OID_AUTO, panic,
     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
     kdb_sysctl_panic, "I",
     "set to panic the kernel");
 
 SYSCTL_PROC(_debug_kdb, OID_AUTO, panic_str,
     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
     kdb_sysctl_panic_str, "A",
     "trigger a kernel panic, using the provided string as the panic message");
 
 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap,
     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, 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 | CTLFLAG_MPSAFE, NULL, 0,
     kdb_sysctl_trap_code, "I",
     "set to cause a page fault via code access");
 
 SYSCTL_PROC(_debug_kdb, OID_AUTO, stack_overflow,
     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
     kdb_sysctl_stack_overflow, "I",
     "set to cause a stack overflow");
 
 SYSCTL_INT(_debug_kdb, OID_AUTO, break_to_debugger,
     CTLFLAG_RWTUN | CTLFLAG_SECURE,
     &kdb_break_to_debugger, 0, "Enable break to debugger");
 
 SYSCTL_INT(_debug_kdb, OID_AUTO, alt_break_to_debugger,
     CTLFLAG_RWTUN | CTLFLAG_SECURE,
     &kdb_alt_break_to_debugger, 0, "Enable alternative 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_panic_str(SYSCTL_HANDLER_ARGS)
 {
 	int error;
 	static char buf[256]; /* static buffer to limit mallocs when panicing */
 
 	*buf = '\0';
 	error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
 	if (error != 0 || req->newptr == NULL)
 		return (error);
 	panic("kdb_sysctl_panic: %s", buf);
 	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);
 }
 
 static void kdb_stack_overflow(volatile int *x)  __noinline;
 static void
 kdb_stack_overflow(volatile int *x)
 {
 
 	if (*x > 10000000)
 		return;
 	kdb_stack_overflow(x);
 	*x += PCPU_GET(cpuid) / 1000000;
 }
 
 static int
 kdb_sysctl_stack_overflow(SYSCTL_HANDLER_ARGS)
 {
 	int error, i;
 	volatile int x;
 
 	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);
 	x = 0;
 	kdb_stack_overflow(&x);
 	return (0);
 }
 
 void
 kdb_panic(const char *msg)
 {
 
 	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_zero(&st);
 		stack_save(&st);
 		stack_print_ddb(&st);
 	}
 #endif
 }
 
 /*
  * Similar to kdb_backtrace() except that it prints a backtrace of an
  * arbitrary thread rather than the calling thread.
  */
 void
 kdb_backtrace_thread(struct thread *td)
 {
 
 	if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace_thread != NULL) {
 		printf("KDB: stack backtrace of thread %d:\n", td->td_tid);
 		kdb_dbbe->dbbe_trace_thread(td);
 	}
 #ifdef STACK
 	else {
 		struct stack st;
 
 		printf("KDB: stack backtrace of thread %d:\n", td->td_tid);
 		if (stack_save_td(&st, td) == 0)
 			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;
 
 	printf("KDB: reentering\n");
 	kdb_backtrace();
 	longjmp(kdb_jmpbufp, 1);
 	/* NOTREACHED */
 }
 
 void
 kdb_reenter_silent(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;
 	u_int i;
 
+	/* This function may be called early. */
+	if (pidhashtbl == NULL)
+		return (&thread0);
+
 	for (i = 0; i <= pidhash; i++) {
 		LIST_FOREACH(p, &pidhashtbl[i], p_hash) {
 			thr = FIRST_THREAD_IN_PROC(p);
 			if (thr != NULL)
 				return (thr);
 		}
 	}
 	return (NULL);
 }
 
 struct thread *
 kdb_thr_from_pid(pid_t pid)
 {
 	struct proc *p;
 
 	LIST_FOREACH(p, PIDHASH(pid), p_hash) {
 		if (p->p_pid == pid)
 			return (FIRST_THREAD_IN_PROC(p));
 	}
 	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;
 	u_int hash;
 
 	p = thr->td_proc;
 	thr = TAILQ_NEXT(thr, td_plist);
 	if (thr != NULL)
 		return (thr);
+	if (pidhashtbl == NULL)
+		return (NULL);
 	hash = p->p_pid & pidhash;
 	for (;;) {
 		p = LIST_NEXT(p, p_hash);
 		while (p == NULL) {
 			if (++hash > pidhash)
 				return (NULL);
 			p = LIST_FIRST(&pidhashtbl[hash]);
 		}
 		thr = FIRST_THREAD_IN_PROC(p);
 		if (thr != NULL)
 			return (thr);
 	}
 }
 
 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;
 	int did_stop_cpus;
 
 	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();
 
 	if (!SCHEDULER_STOPPED()) {
 #ifdef SMP
 		other_cpus = all_cpus;
 		CPU_ANDNOT(&other_cpus, &stopped_cpus);
 		CPU_CLR(PCPU_GET(cpuid), &other_cpus);
 		stop_cpus_hard(other_cpus);
 #endif
 		curthread->td_stopsched = 1;
 		did_stop_cpus = 1;
 	} else
 		did_stop_cpus = 0;
 
 	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);
 
 	cngrab();
 
 	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);
 	}
 
 	cnungrab();
 
 	kdb_active--;
 
 	if (did_stop_cpus) {
 		curthread->td_stopsched = 0;
 #ifdef SMP
 		CPU_AND(&other_cpus, &stopped_cpus);
 		restart_cpus(other_cpus);
 #endif
 	}
 
 	intr_restore(intr);
 
 	return (handled);
 }