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Index: share/man/man9/fail.9
===================================================================
--- share/man/man9/fail.9
+++ share/man/man9/fail.9
@@ -26,25 +26,31 @@
.\"
.\" $FreeBSD$
.\"
-.Dd May 10, 2009
+.Dd February 02, 2016
.Dt FAIL 9
.Os
.Sh NAME
.Nm KFAIL_POINT_CODE ,
+.Nm KFAIL_POINT_CODE_FLAGS ,
+.Nm KFAIL_POINT_CODE_COND ,
.Nm KFAIL_POINT_RETURN ,
.Nm KFAIL_POINT_RETURN_VOID ,
.Nm KFAIL_POINT_ERROR ,
.Nm KFAIL_POINT_GOTO ,
+.Nm KFAIL_POINT_SLEEP_CALLBACKS ,
.Nm fail_point ,
.Nm DEBUG_FP
.Nd fail points
.Sh SYNOPSIS
.In sys/fail.h
.Fn KFAIL_POINT_CODE "parent" "name" "code"
+.Fn KFAIL_POINT_CODE_FLAGS "parent" "name" "flags" "code"
+.Fn KFAIL_POINT_CODE_COND "parent" "name" "cond" "flags" "code"
.Fn KFAIL_POINT_RETURN "parent" "name"
.Fn KFAIL_POINT_RETURN_VOID "parent" "name"
.Fn KFAIL_POINT_ERROR "parent" "name" "error_var"
.Fn KFAIL_POINT_GOTO "parent" "name" "error_var" "label"
+.Fn KFAIL_POINT_SLEEP_CALLBACKS "parent" "name" "pre_func" "pre_arg" "post_func" "post_arg" "code"
.Sh DESCRIPTION
Fail points are used to add code points where errors may be injected
in a user controlled fashion.
@@ -77,6 +83,42 @@
is derived from the
.Fn return
value set in the sysctl MIB.
+.Pp
+Additionally,
+.Fn KFAIL_POINT_CODE_FLAGS
+provides a
+.Fa flags
+argument which controls the fail point's behaviour.
+This can be used to e.g., mark the fail point's context as non-sleepable,
+which causes the
+.Sy sleep
+action to be coerced to a busy wait.
+The supported flags are:
+.Bl -ohang -offset indent
+.It FAIL_POINT_USE_TIMEOUT_PATH
+Rather than sleeping on a
+.Fn sleep
+call, just fire the post-sleep function after a timeout fires.
+.It FAIL_POINT_NONSLEEPABLE
+Mark the fail point as being in a non-sleepable context, which coerces
+.Fn sleep
+calls to
+.Fn delay
+calls.
+.El
+.Pp
+Likewise,
+.Fn KFAIL_POINT_CODE_COND
+supplies a
+.Fa cond
+argument, which allows you to set the condition under which the fail point's
+code may fire.
+This is equivalent to:
+.Bd -literal
+ if (cond)
+ KFAIL_POINT_CODE_FLAGS(...);
+
+.Ed
See
.Sx SYSCTL VARIABLES
below.
@@ -107,26 +149,12 @@
tree (referenced in code by
.Sy DEBUG_FP ) .
.Pp
-The sysctl variable may be set using the following grammar:
+The sysctl variable may be set in a number of ways:
.Bd -literal
- <fail_point> ::
- <term> ( "->" <term> )*
-
- <term> ::
- ( (<float> "%") | (<integer> "*" ) )*
- <type>
- [ "(" <integer> ")" ]
- [ "[pid " <integer> "]" ]
-
- <float> ::
- <integer> [ "." <integer> ] |
- "." <integer>
-
- <type> ::
- "off" | "return" | "sleep" | "panic" | "break" | "print"
+ [<pct>%][<cnt>*]<type>[(args...)][-><more terms>]
.Ed
.Pp
-The <type> argument specifies which action to take:
+The <type> argument specifies which action to take; it can be one of:
.Bl -tag -width ".Dv return"
.It Sy off
Take no action (does not trigger fail point code)
@@ -140,13 +168,23 @@
Break into the debugger, or trap if there is no debugger support
.It Sy print
Print that the fail point executed
+.It Sy pause
+Threads sleep at the fail point until the fail point is set to
+.Sy off
+.It Sy yield
+Thread yields the cpu when the fail point is evaluated
+.It Sy delay
+Similar to sleep, but busy waits the cpu.
+(Useful in non-sleepable contexts.)
.El
.Pp
-The <float>% and <integer>* modifiers prior to <type> control when
+The <pct>% and <cnt>* modifiers prior to <type> control when
<type> is executed.
-The <float>% form (e.g. "1.2%") can be used to specify a
+The <pct>% form (e.g. "1.2%") can be used to specify a
probability that <type> will execute.
-The <integer>* form (e.g. "5*") can be used to specify the number of
+This is a decimal in the range (0, 100] which can specify up to
+1/10,000% precision.
+The <cnt>* form (e.g. "5*") can be used to specify the number of
times <type> should be executed before this <term> is disabled.
Only the last probability and the last count are used if multiple
are specified, i.e. "1.2%2%" is the same as "2%".
@@ -191,6 +229,10 @@
.Sh AUTHORS
.An -nosplit
This manual page was written by
+.Pp
+.An Matthew Bryan Aq Mt matthew.bryan@isilon.com
+and
+.Pp
.An Zach Loafman Aq Mt zml@FreeBSD.org .
.Sh CAVEATS
It is easy to shoot yourself in the foot by setting fail points too
@@ -206,3 +248,10 @@
.Fn fail_point_eval
does not verify whether the context is appropriate for calling
.Fn msleep .
+You can force it to evaluate a
+.Sy sleep
+action as a
+.Sy delay
+action by specifying the
+.Sy FAIL_POINT_NONSLEEPABLE
+flag at the point the fail point is declared.
Index: sys/kern/kern_fail.c
===================================================================
--- sys/kern/kern_fail.c
+++ sys/kern/kern_fail.c
@@ -57,12 +57,18 @@
#include <sys/fail.h>
#include <sys/kernel.h>
#include <sys/libkern.h>
+#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sbuf.h>
+#include <sys/sleepqueue.h>
+#include <sys/sx.h>
+#include <sys/sysctl.h>
+#include <sys/types.h>
+#include <machine/atomic.h>
#include <machine/stdarg.h>
#ifdef ILOG_DEFINE_FOR_FILE
@@ -72,11 +78,45 @@
static MALLOC_DEFINE(M_FAIL_POINT, "Fail Points", "fail points system");
#define fp_free(ptr) free(ptr, M_FAIL_POINT)
#define fp_malloc(size, flags) malloc((size), M_FAIL_POINT, (flags))
+#define fs_free(ptr) fp_free(ptr)
+#define fs_malloc() fp_malloc(sizeof(struct fail_point_setting), \
+ M_WAITOK | M_ZERO)
+
+ /**
+ * These define the wchans that are used for sleeping, pausing respectively.
+ * They are chosen arbitrarily but need to be distinct to the failpoint and
+ * the sleep/pause distinction.
+ */
+#define FP_SLEEP_CHANNEL(fp) (void*)(fp)
+#define FP_PAUSE_CHANNEL(fp) __DEVOLATILE(void*, &fp->fp_setting)
-static struct mtx g_fp_mtx;
-MTX_SYSINIT(g_fp_mtx, &g_fp_mtx, "fail point mtx", MTX_DEF);
-#define FP_LOCK() mtx_lock(&g_fp_mtx)
-#define FP_UNLOCK() mtx_unlock(&g_fp_mtx)
+/**
+ * Don't allow more than this many entries in a fail point set by sysctl.
+ * The 99.99...% case is to have 1 entry. I can't imagine having this many
+ * entries, so it should not limit us. Saves on re-mallocs while holding
+ * a non-sleepable lock.
+ */
+#define FP_MAX_ENTRY_COUNT 20
+
+/* Used to drain sbufs to the sysctl output */
+int fail_sysctl_drain_func(void *, const char *, int);
+
+/* Head of tailq of struct fail_point_entry */
+TAILQ_HEAD(fail_point_entry_queue, fail_point_entry);
+
+/**
+ * fp entries garbage list; outstanding entries are cleaned up in the
+ * garbage collector
+ */
+STAILQ_HEAD(fail_point_setting_garbage, fail_point_setting);
+static struct fail_point_setting_garbage fp_setting_garbage =
+ STAILQ_HEAD_INITIALIZER(fp_setting_garbage);
+static struct mtx mtx_garbage_list;
+MTX_SYSINIT(mtx_garbage_list, &mtx_garbage_list, "fail point garbage mtx",
+ MTX_SPIN);
+
+static struct sx sx_fp_set;
+SX_SYSINIT(sx_fp_set, &sx_fp_set, "fail point set sx");
/**
* Failpoint types.
@@ -90,7 +130,11 @@
FAIL_POINT_BREAK, /**< break into the debugger */
FAIL_POINT_PRINT, /**< print a message */
FAIL_POINT_SLEEP, /**< sleep for some msecs */
- FAIL_POINT_NUMTYPES
+ FAIL_POINT_PAUSE, /**< sleep until failpoint is set to off */
+ FAIL_POINT_YIELD, /**< yield the cpu */
+ FAIL_POINT_DELAY, /**< busy wait the cpu */
+ FAIL_POINT_NUMTYPES,
+ FAIL_POINT_INVALID = -1
};
static struct {
@@ -104,53 +148,308 @@
[FAIL_POINT_BREAK] = FP_TYPE_NM_LEN("break"),
[FAIL_POINT_PRINT] = FP_TYPE_NM_LEN("print"),
[FAIL_POINT_SLEEP] = FP_TYPE_NM_LEN("sleep"),
+ [FAIL_POINT_PAUSE] = FP_TYPE_NM_LEN("pause"),
+ [FAIL_POINT_YIELD] = FP_TYPE_NM_LEN("yield"),
+ [FAIL_POINT_DELAY] = FP_TYPE_NM_LEN("delay"),
};
+#define FE_COUNT_UNTRACKED (INT_MIN)
+
/**
* Internal structure tracking a single term of a complete failpoint.
* @ingroup failpoint_private
*/
struct fail_point_entry {
- enum fail_point_t fe_type; /**< type of entry */
+ volatile bool fe_stale;
+ enum fail_point_t fe_type; /**< type of entry */
int fe_arg; /**< argument to type (e.g. return value) */
int fe_prob; /**< likelihood of firing in millionths */
- int fe_count; /**< number of times to fire, 0 means always */
+ int fe_count; /**< number of times to fire, -1 means infinite */
pid_t fe_pid; /**< only fail for this process */
- TAILQ_ENTRY(fail_point_entry) fe_entries; /**< next entry in fail point */
+ struct fail_point *fe_parent; /**< backpointer to fp */
+ TAILQ_ENTRY(fail_point_entry) fe_entries; /**< next entry ptr */
+};
+
+struct fail_point_setting {
+ STAILQ_ENTRY(fail_point_setting) fs_garbage_link;
+ struct fail_point_entry_queue fp_entry_queue;
+ struct fail_point * fs_parent;
+ struct mtx feq_mtx; /* Gives fail_point_pause something to do. */
+};
+
+/**
+ * Defines stating the equivalent of probablilty one (100%)
+ */
+enum {
+ PROB_MAX = 1000000, /* probability between zero and this number */
+ PROB_DIGITS = 6 /* number of zero's in above number */
};
+/* Get a ref on an fp's fp_setting */
+static inline struct fail_point_setting *fail_point_setting_get_ref(
+ struct fail_point *fp);
+/* Release a ref on an fp_setting */
+static inline void fail_point_setting_release_ref(struct fail_point *fp);
+/* Allocate and initialize a struct fail_point_setting */
+static struct fail_point_setting *fail_point_setting_new(struct
+ fail_point *);
+/* Free a struct fail_point_setting */
+static void fail_point_setting_destroy(struct fail_point_setting *fp_setting);
+/* Allocate and initialize a struct fail_point_entry */
+static struct fail_point_entry *fail_point_entry_new(struct
+ fail_point_setting *);
+/* Free a struct fail_point_entry */
+static void fail_point_entry_destroy(struct fail_point_entry *fp_entry);
+/* Append fp setting to garbage list */
+static inline void fail_point_setting_garbage_append(
+ struct fail_point_setting *fp_setting);
+/* Swap fp's setting with fp_setting_new */
+static inline struct fail_point_setting *
+ fail_point_swap_settings(struct fail_point *fp,
+ struct fail_point_setting *fp_setting_new);
+/* Free up any zero-ref setting in the garbage queue */
+static void fail_point_garbage_collect(void);
+/* If this fail point's setting are empty, then swap it out to NULL. */
+static inline void fail_point_eval_swap_out(struct fail_point *fp,
+ struct fail_point_setting *fp_setting);
+
+bool
+fail_point_is_off(struct fail_point *fp)
+{
+ bool return_val;
+ struct fail_point_setting *fp_setting;
+ struct fail_point_entry *ent;
+
+ return_val = true;
+
+ fp_setting = fail_point_setting_get_ref(fp);
+ if (fp_setting != NULL) {
+ TAILQ_FOREACH(ent, &fp_setting->fp_entry_queue,
+ fe_entries) {
+ if (!ent->fe_stale) {
+ return_val = false;
+ break;
+ }
+ }
+ }
+ fail_point_setting_release_ref(fp);
+
+ return (return_val);
+}
+
+/* Allocate and initialize a struct fail_point_setting */
+static struct fail_point_setting *
+fail_point_setting_new(struct fail_point *fp)
+{
+ struct fail_point_setting *fs_new;
+
+ fs_new = fs_malloc();
+ fs_new->fs_parent = fp;
+ TAILQ_INIT(&fs_new->fp_entry_queue);
+ mtx_init(&fs_new->feq_mtx, "fail point entries", NULL, MTX_SPIN);
+
+ fail_point_setting_garbage_append(fs_new);
+
+ return (fs_new);
+}
+
+/* Free a struct fail_point_setting */
+static void
+fail_point_setting_destroy(struct fail_point_setting *fp_setting)
+{
+ struct fail_point_entry *ent;
+
+ while (!TAILQ_EMPTY(&fp_setting->fp_entry_queue)) {
+ ent = TAILQ_FIRST(&fp_setting->fp_entry_queue);
+ TAILQ_REMOVE(&fp_setting->fp_entry_queue, ent, fe_entries);
+ fail_point_entry_destroy(ent);
+ }
+
+ fs_free(fp_setting);
+}
+
+/* Allocate and initialize a struct fail_point_entry */
+static struct fail_point_entry *
+fail_point_entry_new(struct fail_point_setting *fp_setting)
+{
+ struct fail_point_entry *fp_entry;
+
+ fp_entry = fp_malloc(sizeof(struct fail_point_entry),
+ M_WAITOK | M_ZERO);
+ fp_entry->fe_parent = fp_setting->fs_parent;
+ fp_entry->fe_prob = PROB_MAX;
+ fp_entry->fe_pid = NO_PID;
+ fp_entry->fe_count = FE_COUNT_UNTRACKED;
+ TAILQ_INSERT_TAIL(&fp_setting->fp_entry_queue, fp_entry,
+ fe_entries);
+
+ return (fp_entry);
+}
+
+/* Free a struct fail_point_entry */
+static void
+fail_point_entry_destroy(struct fail_point_entry *fp_entry)
+{
+
+ fp_free(fp_entry);
+}
+
+/* Get a ref on an fp's fp_setting */
+static inline struct fail_point_setting *
+fail_point_setting_get_ref(struct fail_point *fp)
+{
+ struct fail_point_setting *fp_setting;
+
+ /* Invariant: if we have a ref, our pointer to fp_setting is safe */
+ atomic_add_acq_32(&fp->fp_ref_cnt, 1);
+ fp_setting = fp->fp_setting;
+
+ return (fp_setting);
+}
+
+/* Release a ref on an fp_setting */
+static inline void
+fail_point_setting_release_ref(struct fail_point *fp)
+{
+
+ KASSERT(&fp->fp_ref_cnt > 0, ("Attempting to deref w/no refs"));
+ atomic_subtract_rel_32(&fp->fp_ref_cnt, 1);
+}
+
+/* Append fp entries to fp garbage list */
+static inline void
+fail_point_setting_garbage_append(struct fail_point_setting *fp_setting)
+{
+
+ mtx_lock_spin(&mtx_garbage_list);
+ STAILQ_INSERT_TAIL(&fp_setting_garbage, fp_setting,
+ fs_garbage_link);
+ mtx_unlock_spin(&mtx_garbage_list);
+}
+
+/* Swap fp's entries with fp_setting_new */
+static struct fail_point_setting *
+fail_point_swap_settings(struct fail_point *fp,
+ struct fail_point_setting *fp_setting_new)
+{
+ struct fail_point_setting *fp_setting_old;
+
+ fp_setting_old = fp->fp_setting;
+ fp->fp_setting = fp_setting_new;
+
+ return (fp_setting_old);
+}
+
+static inline void
+fail_point_eval_swap_out(struct fail_point *fp,
+ struct fail_point_setting *fp_setting)
+{
+
+ /* We may have already been swapped out and replaced; ignore. */
+ if (fp->fp_setting == fp_setting)
+ fail_point_swap_settings(fp, NULL);
+}
+
+/* Free up any zero-ref entries in the garbage queue */
+static void
+fail_point_garbage_collect()
+{
+ struct fail_point_setting *fs_current, *fs_next;
+ struct fail_point_setting_garbage fp_ents_free_list;
+
+ /**
+ * We will transfer the entries to free to fp_ents_free_list while holding
+ * the spin mutex, then free it after we drop the lock. This avoids
+ * triggering witness due to sleepable mutexes in the memory
+ * allocator.
+ */
+ STAILQ_INIT(&fp_ents_free_list);
+
+ mtx_lock_spin(&mtx_garbage_list);
+ STAILQ_FOREACH_SAFE(fs_current, &fp_setting_garbage, fs_garbage_link,
+ fs_next) {
+ if (fs_current->fs_parent->fp_setting != fs_current &&
+ !atomic_load_acq_32(
+ &fs_current->fs_parent->fp_ref_cnt)) {
+ STAILQ_REMOVE(&fp_setting_garbage, fs_current,
+ fail_point_setting, fs_garbage_link);
+ STAILQ_INSERT_HEAD(&fp_ents_free_list, fs_current,
+ fs_garbage_link);
+ }
+ }
+ mtx_unlock_spin(&mtx_garbage_list);
+
+ STAILQ_FOREACH_SAFE(fs_current, &fp_ents_free_list, fs_garbage_link,
+ fs_next)
+ fail_point_setting_destroy(fs_current);
+}
+
+/* Drain out all refs from this fail point */
+static inline void
+fail_point_drain(struct fail_point *fp, int expected_ref)
+{
+ struct fail_point_setting *entries;
+
+ entries = fail_point_swap_settings(fp, NULL);
+ /**
+ * We have unpaused all threads; so we will wait no longer
+ * than the time taken for the longest remaining sleep, or
+ * the length of time of a long-running code block.
+ */
+ while (atomic_load_acq_32(&fp->fp_ref_cnt) > expected_ref) {
+ wakeup(FP_PAUSE_CHANNEL(fp));
+ tsleep(&fp, PWAIT, "fail_point_drain", hz / 100);
+ }
+ fail_point_swap_settings(fp, entries);
+}
+
static inline void
-fail_point_sleep(struct fail_point *fp, struct fail_point_entry *ent,
- int msecs, enum fail_point_return_code *pret)
+fail_point_pause(struct fail_point *fp, enum fail_point_return_code *pret,
+ struct mtx *mtx_sleep)
{
- /* convert from millisecs to ticks, rounding up */
- int timo = ((msecs * hz) + 999) / 1000;
+
+ if (fp->fp_pre_sleep_fn)
+ fp->fp_pre_sleep_fn(fp->fp_pre_sleep_arg);
+
+ msleep_spin(FP_PAUSE_CHANNEL(fp), mtx_sleep, "failpt", 0);
+
+ if (fp->fp_post_sleep_fn)
+ fp->fp_post_sleep_fn(fp->fp_post_sleep_arg);
+}
+
+static inline void
+fail_point_sleep(struct fail_point *fp, int msecs,
+ enum fail_point_return_code *pret)
+{
+ int timo;
+
+ /* Convert from millisecs to ticks, rounding up */
+ timo = howmany(msecs * hz, 1000);
if (timo > 0) {
- if (fp->fp_sleep_fn == NULL) {
- msleep(fp, &g_fp_mtx, PWAIT, "failpt", timo);
+ if (!(fp->fp_flags & FAIL_POINT_USE_TIMEOUT_PATH)) {
+ if (fp->fp_pre_sleep_fn)
+ fp->fp_pre_sleep_fn(fp->fp_pre_sleep_arg);
+
+ tsleep(FP_SLEEP_CHANNEL(fp), PWAIT, "failpt", timo);
+
+ if (fp->fp_post_sleep_fn)
+ fp->fp_post_sleep_fn(fp->fp_post_sleep_arg);
} else {
- timeout(fp->fp_sleep_fn, fp->fp_sleep_arg, timo);
+ if (fp->fp_pre_sleep_fn)
+ fp->fp_pre_sleep_fn(fp->fp_pre_sleep_arg);
+
+ timeout(fp->fp_post_sleep_fn, fp->fp_post_sleep_arg,
+ timo);
*pret = FAIL_POINT_RC_QUEUED;
}
}
}
-
-/**
- * Defines stating the equivalent of probablilty one (100%)
- */
-enum {
- PROB_MAX = 1000000, /* probability between zero and this number */
- PROB_DIGITS = 6, /* number of zero's in above number */
-};
-
-static char *parse_fail_point(struct fail_point_entries *, char *);
-static char *parse_term(struct fail_point_entries *, char *);
+static char *parse_fail_point(struct fail_point_setting *, char *);
+static char *parse_term(struct fail_point_setting *, char *);
static char *parse_number(int *out_units, int *out_decimal, char *);
static char *parse_type(struct fail_point_entry *, char *);
-static void free_entry(struct fail_point_entries *, struct fail_point_entry *);
-static void clear_entries(struct fail_point_entries *);
/**
* Initialize a fail_point. The name is formed in a printf-like fashion
@@ -167,7 +466,7 @@
char *name;
int n;
- TAILQ_INIT(&fp->fp_entries);
+ fp->fp_setting = NULL;
fp->fp_flags = 0;
/* Figure out the size of the name. */
@@ -185,25 +484,33 @@
fp->fp_name = name;
fp->fp_location = "";
fp->fp_flags |= FAIL_POINT_DYNAMIC_NAME;
- fp->fp_sleep_fn = NULL;
- fp->fp_sleep_arg = NULL;
+ fp->fp_pre_sleep_fn = NULL;
+ fp->fp_pre_sleep_arg = NULL;
+ fp->fp_post_sleep_fn = NULL;
+ fp->fp_post_sleep_arg = NULL;
}
/**
- * Free the resources held by a fail_point.
- *
+ * Free the resources held by a fail_point, and wake any paused threads.
+ * Thou shalt not allow threads to hit this fail point after you enter this
+ * function, nor shall you call this multiple times for a given fp.
* @ingroup failpoint
*/
void
fail_point_destroy(struct fail_point *fp)
{
+ fail_point_drain(fp, 0);
+
if ((fp->fp_flags & FAIL_POINT_DYNAMIC_NAME) != 0) {
fp_free(__DECONST(void *, fp->fp_name));
fp->fp_name = NULL;
}
fp->fp_flags = 0;
- clear_entries(&fp->fp_entries);
+
+ sx_xlock(&sx_fp_set);
+ fail_point_garbage_collect();
+ sx_xunlock(&sx_fp_set);
}
/**
@@ -216,21 +523,43 @@
enum fail_point_return_code
fail_point_eval_nontrivial(struct fail_point *fp, int *return_value)
{
- enum fail_point_return_code ret = FAIL_POINT_RC_CONTINUE;
- struct fail_point_entry *ent, *next;
+ struct fail_point_entry *ent;
+ struct fail_point_setting *fp_setting;
+ enum fail_point_return_code ret;
int msecs;
+ int usecs;
+
+ ret = FAIL_POINT_RC_CONTINUE;
- FP_LOCK();
+ fp_setting = fail_point_setting_get_ref(fp);
+ if (fp_setting == NULL)
+ goto abort;
- TAILQ_FOREACH_SAFE(ent, &fp->fp_entries, fe_entries, next) {
+ TAILQ_FOREACH(ent, &fp_setting->fp_entry_queue, fe_entries) {
int cont = 0; /* don't continue by default */
+ if (ent->fe_stale)
+ continue;
+
if (ent->fe_prob < PROB_MAX &&
ent->fe_prob < random() % PROB_MAX)
continue;
+
if (ent->fe_pid != NO_PID && ent->fe_pid != curproc->p_pid)
continue;
+ /**
+ * No need to force an atomic load, since in the untracked
+ * case the field is unchanging.
+ */
+ if (ent->fe_count != FE_COUNT_UNTRACKED) {
+ if (atomic_load_acq_32(&ent->fe_count) > 0)
+ atomic_subtract_rel_32(&ent->fe_count, 1);
+
+ if (atomic_load_acq_32(&ent->fe_count) <= 0)
+ ent->fe_stale = true;
+ }
+
switch (ent->fe_type) {
case FAIL_POINT_PANIC:
panic("fail point %s panicking", fp->fp_name);
@@ -244,7 +573,7 @@
case FAIL_POINT_BREAK:
printf("fail point %s breaking to debugger\n",
- fp->fp_name);
+ fp->fp_name);
breakpoint();
break;
@@ -254,51 +583,95 @@
break;
case FAIL_POINT_SLEEP:
- /*
- * Free the entry now if necessary, since
- * we're about to drop the mutex and sleep.
- */
msecs = ent->fe_arg;
- if (ent->fe_count > 0 && --ent->fe_count == 0) {
- free_entry(&fp->fp_entries, ent);
- ent = NULL;
- }
-
if (msecs)
- fail_point_sleep(fp, ent, msecs, &ret);
+ fail_point_sleep(fp, msecs, &ret);
+ break;
+
+ case FAIL_POINT_PAUSE:
+ /**
+ * Pausing is inherently strange with multiple
+ * entries given our design. That is because some
+ * entries could be unreachable, for instance in cases like:
+ * pause->return. We can never reach the return entry.
+ * The sysctl layer actually truncates all entries after
+ * a pause for this reason.
+ */
+ mtx_lock_spin(&fp_setting->feq_mtx);
+ fail_point_pause(fp, &ret, &fp_setting->feq_mtx);
+ mtx_unlock_spin(&fp_setting->feq_mtx);
+ break;
+
+ case FAIL_POINT_YIELD:
+ kern_yield(-1);
+ break;
+
+ case FAIL_POINT_DELAY:
+ usecs = ent->fe_arg;
+ DELAY(usecs);
break;
default:
break;
}
- if (ent != NULL && ent->fe_count > 0 && --ent->fe_count == 0)
- free_entry(&fp->fp_entries, ent);
if (cont == 0)
break;
}
- /* Get rid of "off"s at the end. */
- while ((ent = TAILQ_LAST(&fp->fp_entries, fail_point_entries)) &&
- ent->fe_type == FAIL_POINT_OFF)
- free_entry(&fp->fp_entries, ent);
+ if (fail_point_is_off(fp))
+ fail_point_eval_swap_out(fp, fp_setting);
- FP_UNLOCK();
+abort:
+ fail_point_setting_release_ref(fp);
return (ret);
+
}
/**
* Translate internal fail_point structure into human-readable text.
*/
static void
-fail_point_get(struct fail_point *fp, struct sbuf *sb)
+fail_point_get(struct fail_point *fp, struct sbuf *sb,
+ bool verbose)
{
struct fail_point_entry *ent;
+ struct fail_point_setting *fp_setting;
+ struct fail_point_entry *fp_entry_cpy;
+ int cnt_sleeping;
+ int idx;
+ int printed_entry_count;
+
+ cnt_sleeping = 0;
+ idx = 0;
+ printed_entry_count = 0;
+
+ fp_entry_cpy = fp_malloc(sizeof(struct fail_point_entry) *
+ (FP_MAX_ENTRY_COUNT + 1), M_WAITOK);
+
+ fp_setting = fail_point_setting_get_ref(fp);
+
+ if (fp_setting != NULL) {
+ TAILQ_FOREACH(ent, &fp_setting->fp_entry_queue, fe_entries) {
+ if (ent->fe_stale)
+ continue;
- FP_LOCK();
+ KASSERT(printed_entry_count < FP_MAX_ENTRY_COUNT,
+ ("FP entry list larger than allowed"));
+
+ fp_entry_cpy[printed_entry_count] = *ent;
+ ++printed_entry_count;
+ }
+ }
+ fail_point_setting_release_ref(fp);
- TAILQ_FOREACH(ent, &fp->fp_entries, fe_entries) {
+ /* This is our equivalent of a NULL terminator */
+ fp_entry_cpy[printed_entry_count].fe_type = FAIL_POINT_INVALID;
+
+ while (idx < printed_entry_count) {
+ ent = &fp_entry_cpy[idx];
+ ++idx;
if (ent->fe_prob < PROB_MAX) {
int decimal = ent->fe_prob % (PROB_MAX / 100);
int units = ent->fe_prob / (PROB_MAX / 100);
@@ -313,7 +686,7 @@
}
sbuf_printf(sb, "%%");
}
- if (ent->fe_count > 0)
+ if (ent->fe_count >= 0)
sbuf_printf(sb, "%d*", ent->fe_count);
sbuf_printf(sb, "%s", fail_type_strings[ent->fe_type].name);
if (ent->fe_arg)
@@ -323,10 +696,29 @@
if (TAILQ_NEXT(ent, fe_entries))
sbuf_printf(sb, "->");
}
- if (TAILQ_EMPTY(&fp->fp_entries))
+ if (!printed_entry_count)
sbuf_printf(sb, "off");
- FP_UNLOCK();
+ fp_free(fp_entry_cpy);
+ if (verbose) {
+ /* Print number of sleeping threads. queue=0 is the argument
+ * used by msleep when sending our threads to sleep. */
+ sbuf_printf(sb, "\nsleeping_thread_stacks = {\n");
+ sleepq_sbuf_print_stacks(sb, FP_SLEEP_CHANNEL(fp), 0,
+ &cnt_sleeping);
+
+ sbuf_printf(sb, "},\n");
+ sbuf_printf(sb, "sleeping_thread_count = %d,\n",
+ cnt_sleeping);
+
+ sbuf_printf(sb, "paused_thread_stacks = {\n");
+ sleepq_sbuf_print_stacks(sb, FP_PAUSE_CHANNEL(fp), 0,
+ &cnt_sleeping);
+
+ sbuf_printf(sb, "},\n");
+ sbuf_printf(sb, "paused_thread_count = %d\n",
+ cnt_sleeping);
+ }
}
/**
@@ -336,38 +728,91 @@
static int
fail_point_set(struct fail_point *fp, char *buf)
{
- int error = 0;
struct fail_point_entry *ent, *ent_next;
- struct fail_point_entries new_entries;
+ struct fail_point_setting *entries;
+ bool should_wake_paused;
+ bool should_truncate;
+ int error;
+
+ error = 0;
+ should_wake_paused = false;
+ should_truncate = false;
/* Parse new entries. */
- TAILQ_INIT(&new_entries);
- if (!parse_fail_point(&new_entries, buf)) {
- clear_entries(&new_entries);
+ /**
+ * ref protects our new malloc'd stuff from being garbage collected
+ * before we link it.
+ */
+ fail_point_setting_get_ref(fp);
+ entries = fail_point_setting_new(fp);
+ if (parse_fail_point(entries, buf) == NULL) {
+ STAILQ_REMOVE(&fp_setting_garbage, entries,
+ fail_point_setting, fs_garbage_link);
+ fail_point_setting_destroy(entries);
error = EINVAL;
goto end;
}
- FP_LOCK();
-
- /* Move new entries in. */
- TAILQ_SWAP(&fp->fp_entries, &new_entries, fail_point_entry, fe_entries);
- clear_entries(&new_entries);
+ /**
+ * Transfer the entries we are going to keep to a new list.
+ * Get rid of useless zero probability entries, and entries with hit
+ * count 0.
+ * If 'off' is present, and it has no hit count set, then all entries
+ * after it are discarded since they are unreachable.
+ */
+ TAILQ_FOREACH_SAFE(ent, &entries->fp_entry_queue, fe_entries, ent_next) {
+ if (ent->fe_prob == 0 || ent->fe_count == 0) {
+ printf("Discarding entry which cannot execute %s\n",
+ fail_type_strings[ent->fe_type].name);
+ TAILQ_REMOVE(&entries->fp_entry_queue, ent,
+ fe_entries);
+ fp_free(ent);
+ continue;
+ } else if (should_truncate) {
+ printf("Discarding unreachable entry %s\n",
+ fail_type_strings[ent->fe_type].name);
+ TAILQ_REMOVE(&entries->fp_entry_queue, ent,
+ fe_entries);
+ fp_free(ent);
+ continue;
+ }
- /* Get rid of useless zero probability entries. */
- TAILQ_FOREACH_SAFE(ent, &fp->fp_entries, fe_entries, ent_next) {
- if (ent->fe_prob == 0)
- free_entry(&fp->fp_entries, ent);
+ if (ent->fe_type == FAIL_POINT_OFF) {
+ should_wake_paused = true;
+ if (ent->fe_count == FE_COUNT_UNTRACKED) {
+ should_truncate = true;
+ TAILQ_REMOVE(&entries->fp_entry_queue, ent,
+ fe_entries);
+ fp_free(ent);
+ }
+ } else if (ent->fe_type == FAIL_POINT_PAUSE) {
+ should_truncate = true;
+ } else if (ent->fe_type == FAIL_POINT_SLEEP && (fp->fp_flags &
+ FAIL_POINT_NONSLEEPABLE)) {
+ /**
+ * If this fail point is annotated as being in a
+ * non-sleepable ctx, convert sleep to delay and
+ * convert the msec argument to usecs.
+ */
+ printf("Sleep call request on fail point in "
+ "non-sleepable context; using delay instead "
+ "of sleep\n");
+ ent->fe_type = FAIL_POINT_DELAY;
+ ent->fe_arg *= 1000;
+ }
}
- /* Get rid of "off"s at the end. */
- while ((ent = TAILQ_LAST(&fp->fp_entries, fail_point_entries)) &&
- ent->fe_type == FAIL_POINT_OFF)
- free_entry(&fp->fp_entries, ent);
-
- FP_UNLOCK();
+ if (TAILQ_EMPTY(&entries->fp_entry_queue)) {
+ entries = fail_point_swap_settings(fp, NULL);
+ if (entries != NULL)
+ wakeup(FP_PAUSE_CHANNEL(fp));
+ } else {
+ if (should_wake_paused)
+ wakeup(FP_PAUSE_CHANNEL(fp));
+ fail_point_swap_settings(fp, entries);
+ }
- end:
+end:
#ifdef IWARNING
if (error)
IWARNING("Failed to set %s %s to %s",
@@ -377,6 +822,7 @@
fp->fp_name, fp->fp_location, buf);
#endif /* IWARNING */
+ fail_point_setting_release_ref(fp);
return (error);
}
@@ -385,25 +831,33 @@
/**
* Handle kernel failpoint set/get.
*/
+
int
fail_point_sysctl(SYSCTL_HANDLER_ARGS)
{
- struct fail_point *fp = arg1;
- char *buf = NULL;
+ struct fail_point *fp;
+ char *buf;
+ struct sbuf *sb_check;
struct sbuf sb;
int error;
- /* Retrieving */
- sbuf_new(&sb, NULL, 128, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
- fail_point_get(fp, &sb);
- sbuf_trim(&sb);
- error = sbuf_finish(&sb);
- if (error == 0)
- error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
- sbuf_delete(&sb);
+ error = 0;
+ fp = arg1;
+ buf = NULL;
+
+ sb_check = sbuf_new(&sb, NULL, 1024, SBUF_AUTOEXTEND);
+ if (sb_check != &sb)
+ return (ENOMEM);
+
+ sbuf_set_drain(&sb, (sbuf_drain_func *)fail_sysctl_drain_func, req);
/* Setting */
- if (!error && req->newptr) {
+ /**
+ * Lock protects any new entries from being garbage collected before we
+ * can link them to the fail point.
+ */
+ sx_xlock(&sx_fp_set);
+ if (req->newptr) {
if (req->newlen > MAX_FAIL_POINT_BUF) {
error = EINVAL;
goto out;
@@ -417,31 +871,95 @@
buf[req->newlen] = '\0';
error = fail_point_set(fp, buf);
- }
+ }
+
+ fail_point_garbage_collect();
+ sx_xunlock(&sx_fp_set);
+
+ /* Retrieving. */
+ fail_point_get(fp, &sb, false);
out:
- fp_free(buf);
+ sbuf_finish(&sb);
+ sbuf_delete(&sb);
+
+ if (buf)
+ fp_free(buf);
+
return (error);
}
+int
+fail_point_sysctl_status(SYSCTL_HANDLER_ARGS)
+{
+ struct fail_point *fp;
+ struct sbuf sb, *sb_check;
+
+ fp = arg1;
+
+ sb_check = sbuf_new(&sb, NULL, 1024, SBUF_AUTOEXTEND);
+ if (sb_check != &sb)
+ return (ENOMEM);
+
+ sbuf_set_drain(&sb, (sbuf_drain_func *)fail_sysctl_drain_func, req);
+
+ /* Retrieving. */
+ fail_point_get(fp, &sb, true);
+
+ sbuf_finish(&sb);
+ sbuf_delete(&sb);
+
+ /**
+ * Lock protects any new entries from being garbage collected before we
+ * can link them to the fail point.
+ */
+ sx_xlock(&sx_fp_set);
+ fail_point_garbage_collect();
+ sx_xunlock(&sx_fp_set);
+
+ return (0);
+}
+
+int
+fail_sysctl_drain_func(void *sysctl_args, const char *buf, int len)
+{
+ struct sysctl_req *sa;
+ int error;
+
+ sa = sysctl_args;
+
+ error = SYSCTL_OUT(sa, buf, len);
+
+ if (error == ENOMEM)
+ return (-1);
+ else
+ return (len);
+}
+
+
/**
* Internal helper function to translate a human-readable failpoint string
* into a internally-parsable fail_point structure.
*/
static char *
-parse_fail_point(struct fail_point_entries *ents, char *p)
+parse_fail_point(struct fail_point_setting *ents, char *p)
{
/* <fail_point> ::
* <term> ( "->" <term> )*
*/
+ uint8_t term_count;
+
+ term_count = 1;
+
p = parse_term(ents, p);
if (p == NULL)
return (NULL);
+
while (*p != '\0') {
- if (p[0] != '-' || p[1] != '>')
- return (NULL);
- p = parse_term(ents, p + 2);
- if (p == NULL)
+ term_count++;
+ if (p[0] != '-' || p[1] != '>' ||
+ (p = parse_term(ents, p+2)) == NULL ||
+ term_count > FP_MAX_ENTRY_COUNT)
return (NULL);
}
return (p);
@@ -451,14 +969,11 @@
* Internal helper function to parse an individual term from a failpoint.
*/
static char *
-parse_term(struct fail_point_entries *ents, char *p)
+parse_term(struct fail_point_setting *ents, char *p)
{
struct fail_point_entry *ent;
- ent = fp_malloc(sizeof *ent, M_WAITOK | M_ZERO);
- ent->fe_prob = PROB_MAX;
- ent->fe_pid = NO_PID;
- TAILQ_INSERT_TAIL(ents, ent, fe_entries);
+ ent = fail_point_entry_new(ents);
/*
* <term> ::
@@ -483,7 +998,7 @@
if (ent->fe_prob > PROB_MAX)
ent->fe_prob = PROB_MAX;
} else if (*p == '*') {
- if (!units || decimal)
+ if (!units || units < 0 || decimal)
return (NULL);
ent->fe_count = units;
} else
@@ -500,7 +1015,7 @@
/* [ "(" <integer> ")" ] */
if (*p != '(')
- return p;
+ return (p);
p++;
if (!isdigit(*p) && *p != '-')
return (NULL);
@@ -509,7 +1024,7 @@
return (NULL);
/* [ "[pid " <integer> "]" ] */
-#define PID_STRING "[pid "
+#define PID_STRING "[pid "
if (strncmp(p, PID_STRING, sizeof(PID_STRING) - 1) != 0)
return (p);
p += sizeof(PID_STRING) - 1;
@@ -530,7 +1045,7 @@
{
char *old_p;
- /*
+ /**
* <number> ::
* <integer> [ "." <integer> ] |
* "." <integer>
@@ -584,29 +1099,17 @@
return (NULL);
}
-/**
- * Internal helper function to free an individual failpoint term.
- */
-static void
-free_entry(struct fail_point_entries *ents, struct fail_point_entry *ent)
-{
- TAILQ_REMOVE(ents, ent, fe_entries);
- fp_free(ent);
-}
+/* The fail point sysctl tree. */
+SYSCTL_NODE(_debug, OID_AUTO, fail_point, CTLFLAG_RW, 0, "fail points");
-/**
- * Internal helper function to clear out all failpoint terms for a single
- * failpoint.
- */
-static void
-clear_entries(struct fail_point_entries *ents)
+/* Debugging/testing stuff for fail point */
+static int
+sysctl_test_fail_point(SYSCTL_HANDLER_ARGS)
{
- struct fail_point_entry *ent, *ent_next;
- TAILQ_FOREACH_SAFE(ent, ents, fe_entries, ent_next)
- fp_free(ent);
- TAILQ_INIT(ents);
+ KFAIL_POINT_RETURN(DEBUG_FP, test_fail_point);
+ return (0);
}
-
-/* The fail point sysctl tree. */
-SYSCTL_NODE(_debug, OID_AUTO, fail_point, CTLFLAG_RW, 0, "fail points");
+SYSCTL_OID(_debug_fail_point, OID_AUTO, test_trigger_fail_point,
+ CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, sysctl_test_fail_point, "A",
+ "Trigger test fail points");
Index: sys/kern/subr_sleepqueue.c
===================================================================
--- sys/kern/subr_sleepqueue.c
+++ sys/kern/subr_sleepqueue.c
@@ -75,6 +75,7 @@
#include <sys/sdt.h>
#include <sys/signalvar.h>
#include <sys/sleepqueue.h>
+#include <sys/stack.h>
#include <sys/sysctl.h>
#include <vm/uma.h>
@@ -83,6 +84,7 @@
#include <ddb/ddb.h>
#endif
+
/*
* Constants for the hash table of sleep queue chains.
* SC_TABLESIZE must be a power of two for SC_MASK to work properly.
@@ -1033,6 +1035,120 @@
return (sleepq_resume_thread(sq, td, 0));
}
+/*
+ * Prints the stacks of all threads presently sleeping on wchan/queue to
+ * the sbuf sb. Sets count_stacks_printed to the number of stacks actually
+ * printed. Typically, this will equal the number of threads sleeping on the
+ * queue, but may be less if sb overflowed before all stacks were printed.
+ */
+int
+sleepq_sbuf_print_stacks(struct sbuf *sb, void *wchan, int queue,
+ int *count_stacks_printed)
+{
+ struct thread *td, *td_next;
+ struct sleepqueue *sq;
+ struct stack **st;
+ struct sbuf **td_infos;
+ int i, stack_idx, error, stacks_to_allocate;
+ bool finished, partial_print;
+
+ error = 0;
+ finished = false;
+ partial_print = false;
+
+ KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__));
+ MPASS((queue >= 0) && (queue < NR_SLEEPQS));
+
+ stacks_to_allocate = 10;
+ for (i = 0; i < 3 && !finished ; i++) {
+ /* We cannot malloc while holding the queue's spinlock, so
+ * we do our mallocs now, and hope it is enough. If it
+ * isn't, we will free these, drop the lock, malloc more,
+ * and try again, up to a point. After that point we will
+ * give up and report ENOMEM. We also cannot write to sb
+ * during this time since the client may have set the
+ * SBUF_AUTOEXTEND flag on their sbuf, which could cause a
+ * malloc as we print to it. So we defer actually printing
+ * to sb until after we drop the spinlock.
+ */
+
+ /* Where we will store the stacks. */
+ st = malloc(sizeof(struct stack *) * stacks_to_allocate,
+ M_TEMP, M_WAITOK);
+ for (stack_idx = 0; stack_idx < stacks_to_allocate;
+ stack_idx++)
+ st[stack_idx] = stack_create();
+
+ /* Where we will store the td name, tid, etc. */
+ td_infos = malloc(sizeof(struct sbuf *) * stacks_to_allocate,
+ M_TEMP, M_WAITOK);
+ for (stack_idx = 0; stack_idx < stacks_to_allocate;
+ stack_idx++)
+ td_infos[stack_idx] = sbuf_new(NULL, NULL,
+ MAXCOMLEN + sizeof(struct thread *) * 2 + 40,
+ SBUF_FIXEDLEN);
+
+ sleepq_lock(wchan);
+ sq = sleepq_lookup(wchan);
+ if (sq == NULL) {
+ /* This sleepq does not exist; exit and return ENOENT. */
+ error = ENOENT;
+ finished = true;
+ sleepq_release(wchan);
+ goto loop_end;
+ }
+
+ stack_idx = 0;
+ /* Save thread info */
+ TAILQ_FOREACH_SAFE(td, &sq->sq_blocked[queue], td_slpq,
+ td_next) {
+ if (stack_idx >= stacks_to_allocate)
+ goto loop_end;
+
+ /* Note the td_lock is equal to the sleepq_lock here. */
+ stack_save_td(st[stack_idx], td);
+
+ sbuf_printf(td_infos[stack_idx], "%d: %s %p",
+ td->td_tid, td->td_name, td);
+
+ ++stack_idx;
+ }
+
+ finished = true;
+ sleepq_release(wchan);
+
+ /* Print the stacks */
+ for (i = 0; i < stack_idx; i++) {
+ sbuf_finish(td_infos[i]);
+ sbuf_printf(sb, "--- thread %s: ---\n", sbuf_data(td_infos[i]));
+ stack_sbuf_print(sb, st[i]);
+ sbuf_printf(sb, "\n");
+
+ error = sbuf_error(sb);
+ if (error == 0)
+ *count_stacks_printed = stack_idx;
+ }
+
+loop_end:
+ if (!finished)
+ sleepq_release(wchan);
+ for (stack_idx = 0; stack_idx < stacks_to_allocate;
+ stack_idx++)
+ stack_destroy(st[stack_idx]);
+ for (stack_idx = 0; stack_idx < stacks_to_allocate;
+ stack_idx++)
+ sbuf_delete(td_infos[stack_idx]);
+ free(st, M_TEMP);
+ free(td_infos, M_TEMP);
+ stacks_to_allocate *= 10;
+ }
+
+ if (!finished && error == 0)
+ error = ENOMEM;
+
+ return (error);
+}
+
#ifdef SLEEPQUEUE_PROFILING
#define SLEEPQ_PROF_LOCATIONS 1024
#define SLEEPQ_SBUFSIZE 512
Index: sys/sys/fail.h
===================================================================
--- sys/sys/fail.h
+++ sys/sys/fail.h
@@ -37,6 +37,11 @@
#include <sys/linker_set.h>
#include <sys/queue.h>
#include <sys/sysctl.h>
+#include <sys/condvar.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/systm.h>
/**
* Failpoint return codes, used internally.
@@ -49,7 +54,8 @@
};
struct fail_point_entry;
-TAILQ_HEAD(fail_point_entries, fail_point_entry);
+struct fail_point_setting;
+
/**
* Internal failpoint structure, tracking all the current details of the
* failpoint. This structure is the core component shared between the
@@ -57,22 +63,42 @@
* @ingroup failpoint_private
*/
struct fail_point {
- const char *fp_name; /**< name of fail point */
- const char *fp_location; /**< file:line of fail point */
- struct fail_point_entries fp_entries; /**< list of entries */
+ const char *fp_name; /* name of fail point */
+ const char *fp_location; /* file:line of fail point */
+ volatile int fp_ref_cnt; /**
+ * protects fp_setting: while holding
+ * a ref, fp_setting points to an
+ * unfreed fail_point_setting
+ */
+ struct fail_point_setting * volatile fp_setting;
int fp_flags;
- void (*fp_sleep_fn)(void *); /**< Function to call at end of
- * sleep for sleep failpoints */
- void *fp_sleep_arg; /**< Arg for sleep_fn */
+
+ /**< Function to call before sleep or pause */
+ void (*fp_pre_sleep_fn)(void *);
+ /**< Arg for fp_pre_sleep_fn */
+ void *fp_pre_sleep_arg;
+
+ /**< Function to call after waking from sleep or pause */
+ void (*fp_post_sleep_fn)(void *);
+ /**< Arg for fp_post_sleep_fn */
+ void *fp_post_sleep_arg;
};
#define FAIL_POINT_DYNAMIC_NAME 0x01 /**< Must free name on destroy */
+/**< Use timeout path for sleep instead of msleep */
+#define FAIL_POINT_USE_TIMEOUT_PATH 0x02
+/**< If fail point is set to sleep, replace the sleep call with delay */
+#define FAIL_POINT_NONSLEEPABLE 0x04
+
+#define FAIL_POINT_CV_DESC "fp cv no iterators"
+#define FAIL_POINT_IS_OFF(fp) (__predict_true((fp)->fp_setting == NULL) || \
+ __predict_true(fail_point_is_off(fp)))
__BEGIN_DECLS
/* Private failpoint eval function -- use fail_point_eval() instead. */
enum fail_point_return_code fail_point_eval_nontrivial(struct fail_point *,
- int *ret);
+ int *ret);
/**
* @addtogroup failpoint
@@ -86,26 +112,62 @@
void fail_point_init(struct fail_point *, const char *fmt, ...)
__printflike(2, 3);
+/* Return true iff this fail point is set to off, false otherwise */
+bool fail_point_is_off(struct fail_point *fp);
+
/**
- * Set the sleep function for a fail point
- * If sleep_fn is specified, then FAIL_POINT_SLEEP will result in a
- * (*fp->sleep_fn)(fp->sleep_arg) call by the timer thread. Otherwise,
- * if sleep_fn is NULL (default), then FAIL_POINT_SLEEP will result in the
- * fail_point_eval() call sleeping.
+ * Set the pre-sleep function for a fail point
+ * If fp_post_sleep_fn is specified, then FAIL_POINT_SLEEP will result in a
+ * (*fp->fp_pre_sleep_fn)(fp->fp_pre_sleep_arg) call by the thread.
*/
-static __inline void
-fail_point_sleep_set_func(struct fail_point *fp, void (*sleep_fn)(void *))
+static inline void
+fail_point_sleep_set_pre_func(struct fail_point *fp, void (*sleep_fn)(void *))
+{
+ fp->fp_pre_sleep_fn = sleep_fn;
+}
+
+static inline void
+fail_point_sleep_set_pre_arg(struct fail_point *fp, void *sleep_arg)
{
- fp->fp_sleep_fn = sleep_fn;
+ fp->fp_pre_sleep_arg = sleep_arg;
}
/**
- * Set the argument for the sleep function for a fail point
+ * Set the post-sleep function. This will be passed to timeout if we take
+ * the timeout path. This must be set if you sleep using the timeout path.
*/
-static __inline void
-fail_point_sleep_set_arg(struct fail_point *fp, void *sleep_arg)
+static inline void
+fail_point_sleep_set_post_func(struct fail_point *fp, void (*sleep_fn)(void *))
+{
+ fp->fp_post_sleep_fn = sleep_fn;
+}
+
+static inline void
+fail_point_sleep_set_post_arg(struct fail_point *fp, void *sleep_arg)
+{
+ fp->fp_post_sleep_arg = sleep_arg;
+}
+/**
+ * If the FAIL_POINT_USE_TIMEOUT flag is set on a failpoint, then
+ * FAIL_POINT_SLEEP will result in a call to timeout instead of
+ * msleep. Note that if you sleep while this flag is set, you must
+ * set fp_post_sleep_fn or an error will occur upon waking.
+ */
+static inline void
+fail_point_use_timeout_path(struct fail_point *fp, bool use_timeout,
+ void (*post_sleep_fn)(void *))
{
- fp->fp_sleep_arg = sleep_arg;
+ KASSERT(!use_timeout || post_sleep_fn != NULL ||
+ (post_sleep_fn == NULL && fp->fp_post_sleep_fn != NULL),
+ ("Setting fp to use timeout, but not setting post_sleep_fn\n"));
+
+ if (use_timeout)
+ fp->fp_flags |= FAIL_POINT_USE_TIMEOUT_PATH;
+ else
+ fp->fp_flags &= ~FAIL_POINT_USE_TIMEOUT_PATH;
+
+ if (post_sleep_fn != NULL)
+ fp->fp_post_sleep_fn = post_sleep_fn;
}
/**
@@ -116,33 +178,64 @@
/**
* Evaluate a failpoint.
*/
-static __inline enum fail_point_return_code
+static inline enum fail_point_return_code
fail_point_eval(struct fail_point *fp, int *ret)
{
- if (TAILQ_EMPTY(&fp->fp_entries)) {
+ if (__predict_true(fp->fp_setting == NULL))
return (FAIL_POINT_RC_CONTINUE);
- }
return (fail_point_eval_nontrivial(fp, ret));
}
__END_DECLS
/* Declare a fail_point and its sysctl in a function. */
-#define _FAIL_POINT_NAME(name) _fail_point_##name
-#define _FAIL_POINT_LOCATION() "(" __FILE__ ":" __XSTRING(__LINE__) ")"
+#define _FAIL_POINT_NAME(name) _fail_point_##name
+#define _FAIL_POINT_LOCATION() "(" __FILE__ ":" __XSTRING(__LINE__) ")"
+#define _FAIL_POINT_INIT(parent, name, flags) \
+ static struct fail_point _FAIL_POINT_NAME(name) = { \
+ .fp_name = #name, \
+ .fp_location = _FAIL_POINT_LOCATION(), \
+ .fp_ref_cnt = 0, \
+ .fp_setting = NULL, \
+ .fp_flags = (flags), \
+ .fp_pre_sleep_fn = NULL, \
+ .fp_pre_sleep_arg = NULL, \
+ .fp_post_sleep_fn = NULL, \
+ .fp_post_sleep_arg = NULL, \
+ }; \
+ SYSCTL_OID(parent, OID_AUTO, name, \
+ CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, \
+ &_FAIL_POINT_NAME(name), 0, fail_point_sysctl, \
+ "A", ""); \
+ SYSCTL_OID(parent, OID_AUTO, status_##name, \
+ CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, \
+ &_FAIL_POINT_NAME(name), 0, \
+ fail_point_sysctl_status, "A", "");
+#define _FAIL_POINT_EVAL(name, cond, code...) \
+ int RETURN_VALUE; \
+ \
+ if (__predict_false(cond && \
+ fail_point_eval(&_FAIL_POINT_NAME(name), &RETURN_VALUE))) { \
+ \
+ code; \
+ \
+ }
+
/**
- * Instantiate a failpoint which returns "value" from the function when triggered.
- * @param parent The parent sysctl under which to locate the sysctl
+ * Instantiate a failpoint which returns "RETURN_VALUE" from the function
+ * when triggered.
+ * @param parent The parent sysctl under which to locate the fp's sysctl
* @param name The name of the failpoint in the sysctl tree (and printouts)
- * @return Instantly returns the return("value") specified in the
+ * @return Instantly returns the RETURN_VALUE specified in the
* failpoint, if triggered.
*/
#define KFAIL_POINT_RETURN(parent, name) \
KFAIL_POINT_CODE(parent, name, return RETURN_VALUE)
/**
- * Instantiate a failpoint which returns (void) from the function when triggered.
+ * Instantiate a failpoint which returns (void) from the function when
+ * triggered.
* @param parent The parent sysctl under which to locate the sysctl
* @param name The name of the failpoint in the sysctl tree (and printouts)
* @return Instantly returns void, if triggered in the failpoint.
@@ -153,7 +246,8 @@
/**
* Instantiate a failpoint which sets an error when triggered.
* @param parent The parent sysctl under which to locate the sysctl
- * @param name The name of the failpoint in the sysctl tree (and printouts)
+ * @param name The name of the failpoint in the sysctl tree (and
+ * printouts)
* @param error_var A variable to set to the failpoint's specified
* return-value when triggered
*/
@@ -164,7 +258,8 @@
* Instantiate a failpoint which sets an error and then goes to a
* specified label in the function when triggered.
* @param parent The parent sysctl under which to locate the sysctl
- * @param name The name of the failpoint in the sysctl tree (and printouts)
+ * @param name The name of the failpoint in the sysctl tree (and
+ * printouts)
* @param error_var A variable to set to the failpoint's specified
* return-value when triggered
* @param label The location to goto when triggered.
@@ -173,39 +268,81 @@
KFAIL_POINT_CODE(parent, name, (error_var) = RETURN_VALUE; goto label)
/**
+ * Instantiate a failpoint which sets its pre- and post-sleep callback
+ * mechanisms.
+ * @param parent The parent sysctl under which to locate the sysctl
+ * @param name The name of the failpoint in the sysctl tree (and
+ * printouts)
+ * @param pre_func Function pointer to the pre-sleep function, which will be
+ * called directly before going to sleep.
+ * @param pre_arg Argument to the pre-sleep function
+ * @param post_func Function pointer to the pot-sleep function, which will be
+ * called directly before going to sleep.
+ * @param post_arg Argument to the post-sleep function
+ */
+#define KFAIL_POINT_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \
+ post_func, post_arg) \
+ KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, \
+ pre_arg, post_func, post_arg, return RETURN_VALUE)
+
+/**
+ * Instantiate a failpoint which runs arbitrary code when triggered, and sets
+ * its pre- and post-sleep callback mechanisms
+ * @param parent The parent sysctl under which to locate the sysctl
+ * @param name The name of the failpoint in the sysctl tree (and
+ * printouts)
+ * @param pre_func Function pointer to the pre-sleep function, which will be
+ * called directly before going to sleep.
+ * @param pre_arg Argument to the pre-sleep function
+ * @param post_func Function pointer to the pot-sleep function, which will be
+ * called directly before going to sleep.
+ * @param post_arg Argument to the post-sleep function
+ * @param code The arbitrary code to run when triggered. Can reference
+ * "RETURN_VALUE" if desired to extract the specified
+ * user return-value when triggered. Note that this is
+ * implemented with a do-while loop so be careful of
+ * break and continue statements.
+ */
+#define KFAIL_POINT_CODE_SLEEP_CALLBACKS(parent, name, pre_func, pre_arg, \
+ post_func, post_arg, code...) \
+ do { \
+ _FAIL_POINT_INIT(parent, name) \
+ _FAIL_POINT_NAME(name).fp_pre_sleep_fn = pre_func; \
+ _FAIL_POINT_NAME(name).fp_pre_sleep_arg = pre_arg; \
+ _FAIL_POINT_NAME(name).fp_post_sleep_fn = post_func; \
+ _FAIL_POINT_NAME(name).fp_post_sleep_arg = post_arg; \
+ _FAIL_POINT_EVAL(name, true, code) \
+ } while (0)
+
+
+/**
* Instantiate a failpoint which runs arbitrary code when triggered.
* @param parent The parent sysctl under which to locate the sysctl
* @param name The name of the failpoint in the sysctl tree
- * (and printouts)
+ * (and printouts)
* @param code The arbitrary code to run when triggered. Can reference
* "RETURN_VALUE" if desired to extract the specified
* user return-value when triggered. Note that this is
* implemented with a do-while loop so be careful of
* break and continue statements.
*/
-#define KFAIL_POINT_CODE(parent, name, code) \
-do { \
- int RETURN_VALUE; \
- static struct fail_point _FAIL_POINT_NAME(name) = { \
- #name, \
- _FAIL_POINT_LOCATION(), \
- TAILQ_HEAD_INITIALIZER(_FAIL_POINT_NAME(name).fp_entries), \
- 0, \
- NULL, NULL, \
- }; \
- SYSCTL_OID(parent, OID_AUTO, name, \
- CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, \
- &_FAIL_POINT_NAME(name), 0, fail_point_sysctl, \
- "A", ""); \
- \
- if (__predict_false( \
- fail_point_eval(&_FAIL_POINT_NAME(name), &RETURN_VALUE))) { \
- \
- code; \
- \
- } \
-} while (0)
-
+#define KFAIL_POINT_CODE(parent, name, code...) \
+ do { \
+ _FAIL_POINT_INIT(parent, name, 0) \
+ _FAIL_POINT_EVAL(name, true, code) \
+ } while (0)
+
+#define KFAIL_POINT_CODE_FLAGS(parent, name, flags, code...) \
+ do { \
+ _FAIL_POINT_INIT(parent, name, flags) \
+ _FAIL_POINT_EVAL(name, true, code) \
+ } while (0)
+
+#define KFAIL_POINT_CODE_COND(parent, name, cond, flags, code...) \
+ do { \
+ _FAIL_POINT_INIT(parent, name, flags) \
+ _FAIL_POINT_EVAL(name, cond, code) \
+ } while (0)
/**
* @}
@@ -214,6 +351,7 @@
#ifdef _KERNEL
int fail_point_sysctl(SYSCTL_HANDLER_ARGS);
+int fail_point_sysctl_status(SYSCTL_HANDLER_ARGS);
/* The fail point sysctl tree. */
SYSCTL_DECL(_debug_fail_point);
Index: sys/sys/sleepqueue.h
===================================================================
--- sys/sys/sleepqueue.h
+++ sys/sys/sleepqueue.h
@@ -107,5 +107,9 @@
void sleepq_wait(void *wchan, int pri);
int sleepq_wait_sig(void *wchan, int pri);
+#include <sys/sbuf.h>
+int sleepq_sbuf_print_stacks(struct sbuf *sb, void *wchan, int queue,
+ int *count_stacks_printed);
+
#endif /* _KERNEL */
#endif /* !_SYS_SLEEPQUEUE_H_ */

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