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-rw-r--r--module/spl/spl-condvar.c55
-rw-r--r--module/splat/splat-condvar.c30
2 files changed, 70 insertions, 15 deletions
diff --git a/module/spl/spl-condvar.c b/module/spl/spl-condvar.c
index c3467a56e..c420d18ca 100644
--- a/module/spl/spl-condvar.c
+++ b/module/spl/spl-condvar.c
@@ -80,6 +80,7 @@ static void
cv_wait_common(kcondvar_t *cvp, kmutex_t *mp, int state, int io)
{
DEFINE_WAIT(wait);
+ kmutex_t *m;
ASSERT(cvp);
ASSERT(mp);
@@ -87,11 +88,11 @@ cv_wait_common(kcondvar_t *cvp, kmutex_t *mp, int state, int io)
ASSERT(mutex_owned(mp));
atomic_inc(&cvp->cv_refs);
- if (cvp->cv_mutex == NULL)
- cvp->cv_mutex = mp;
-
+ m = ACCESS_ONCE(cvp->cv_mutex);
+ if (!m)
+ m = xchg(&cvp->cv_mutex, mp);
/* Ensure the same mutex is used by all callers */
- ASSERT(cvp->cv_mutex == mp);
+ ASSERT(m == NULL || m == mp);
prepare_to_wait_exclusive(&cvp->cv_event, &wait, state);
atomic_inc(&cvp->cv_waiters);
@@ -106,16 +107,25 @@ cv_wait_common(kcondvar_t *cvp, kmutex_t *mp, int state, int io)
io_schedule();
else
schedule();
- mutex_enter(mp);
/* No more waiters a different mutex could be used */
if (atomic_dec_and_test(&cvp->cv_waiters)) {
+ /*
+ * This is set without any lock, so it's racy. But this is
+ * just for debug anyway, so make it best-effort
+ */
cvp->cv_mutex = NULL;
wake_up(&cvp->cv_destroy);
}
finish_wait(&cvp->cv_event, &wait);
atomic_dec(&cvp->cv_refs);
+
+ /*
+ * Hold mutex after we release the cvp, otherwise we could dead lock
+ * with a thread holding the mutex and call cv_destroy.
+ */
+ mutex_enter(mp);
}
void
@@ -148,6 +158,7 @@ __cv_timedwait_common(kcondvar_t *cvp, kmutex_t *mp, clock_t expire_time,
int state)
{
DEFINE_WAIT(wait);
+ kmutex_t *m;
clock_t time_left;
ASSERT(cvp);
@@ -156,15 +167,16 @@ __cv_timedwait_common(kcondvar_t *cvp, kmutex_t *mp, clock_t expire_time,
ASSERT(mutex_owned(mp));
atomic_inc(&cvp->cv_refs);
- if (cvp->cv_mutex == NULL)
- cvp->cv_mutex = mp;
-
+ m = ACCESS_ONCE(cvp->cv_mutex);
+ if (!m)
+ m = xchg(&cvp->cv_mutex, mp);
/* Ensure the same mutex is used by all callers */
- ASSERT(cvp->cv_mutex == mp);
+ ASSERT(m == NULL || m == mp);
/* XXX - Does not handle jiffie wrap properly */
time_left = expire_time - jiffies;
if (time_left <= 0) {
+ /* XXX - doesn't reset cv_mutex */
atomic_dec(&cvp->cv_refs);
return (-1);
}
@@ -179,10 +191,13 @@ __cv_timedwait_common(kcondvar_t *cvp, kmutex_t *mp, clock_t expire_time,
*/
mutex_exit(mp);
time_left = schedule_timeout(time_left);
- mutex_enter(mp);
/* No more waiters a different mutex could be used */
if (atomic_dec_and_test(&cvp->cv_waiters)) {
+ /*
+ * This is set without any lock, so it's racy. But this is
+ * just for debug anyway, so make it best-effort
+ */
cvp->cv_mutex = NULL;
wake_up(&cvp->cv_destroy);
}
@@ -190,6 +205,11 @@ __cv_timedwait_common(kcondvar_t *cvp, kmutex_t *mp, clock_t expire_time,
finish_wait(&cvp->cv_event, &wait);
atomic_dec(&cvp->cv_refs);
+ /*
+ * Hold mutex after we release the cvp, otherwise we could dead lock
+ * with a thread holding the mutex and call cv_destroy.
+ */
+ mutex_enter(mp);
return (time_left > 0 ? time_left : -1);
}
@@ -216,6 +236,7 @@ __cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t expire_time,
int state)
{
DEFINE_WAIT(wait);
+ kmutex_t *m;
hrtime_t time_left, now;
unsigned long time_left_us;
@@ -225,11 +246,11 @@ __cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t expire_time,
ASSERT(mutex_owned(mp));
atomic_inc(&cvp->cv_refs);
- if (cvp->cv_mutex == NULL)
- cvp->cv_mutex = mp;
-
+ m = ACCESS_ONCE(cvp->cv_mutex);
+ if (!m)
+ m = xchg(&cvp->cv_mutex, mp);
/* Ensure the same mutex is used by all callers */
- ASSERT(cvp->cv_mutex == mp);
+ ASSERT(m == NULL || m == mp);
now = gethrtime();
time_left = expire_time - now;
@@ -253,10 +274,13 @@ __cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t expire_time,
* interrupts
*/
usleep_range(time_left_us, time_left_us + 100);
- mutex_enter(mp);
/* No more waiters a different mutex could be used */
if (atomic_dec_and_test(&cvp->cv_waiters)) {
+ /*
+ * This is set without any lock, so it's racy. But this is
+ * just for debug anyway, so make it best-effort
+ */
cvp->cv_mutex = NULL;
wake_up(&cvp->cv_destroy);
}
@@ -264,6 +288,7 @@ __cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t expire_time,
finish_wait(&cvp->cv_event, &wait);
atomic_dec(&cvp->cv_refs);
+ mutex_enter(mp);
time_left = expire_time - gethrtime();
return (time_left > 0 ? time_left : -1);
}
diff --git a/module/splat/splat-condvar.c b/module/splat/splat-condvar.c
index af40a7258..bdbaf79c8 100644
--- a/module/splat/splat-condvar.c
+++ b/module/splat/splat-condvar.c
@@ -88,6 +88,9 @@ splat_condvar_test12_thread(void *arg)
ct->ct_thread->comm, atomic_read(&cv->cv_condvar.cv_waiters));
mutex_exit(&cv->cv_mtx);
+ /* wait for main thread reap us */
+ while (!kthread_should_stop())
+ schedule();
return 0;
}
@@ -151,6 +154,12 @@ splat_condvar_test1(struct file *file, void *arg)
/* Wake everything for the failure case */
cv_broadcast(&cv.cv_condvar);
cv_destroy(&cv.cv_condvar);
+
+ /* wait for threads to exit */
+ for (i = 0; i < SPLAT_CONDVAR_TEST_COUNT; i++) {
+ if (!IS_ERR(ct[i].ct_thread))
+ kthread_stop(ct[i].ct_thread);
+ }
mutex_destroy(&cv.cv_mtx);
return rc;
@@ -199,6 +208,12 @@ splat_condvar_test2(struct file *file, void *arg)
/* Wake everything for the failure case */
cv_destroy(&cv.cv_condvar);
+
+ /* wait for threads to exit */
+ for (i = 0; i < SPLAT_CONDVAR_TEST_COUNT; i++) {
+ if (!IS_ERR(ct[i].ct_thread))
+ kthread_stop(ct[i].ct_thread);
+ }
mutex_destroy(&cv.cv_mtx);
return rc;
@@ -234,6 +249,9 @@ splat_condvar_test34_thread(void *arg)
mutex_exit(&cv->cv_mtx);
+ /* wait for main thread reap us */
+ while (!kthread_should_stop())
+ schedule();
return 0;
}
@@ -302,6 +320,12 @@ splat_condvar_test3(struct file *file, void *arg)
/* Wake everything for the failure case */
cv_broadcast(&cv.cv_condvar);
cv_destroy(&cv.cv_condvar);
+
+ /* wait for threads to exit */
+ for (i = 0; i < SPLAT_CONDVAR_TEST_COUNT; i++) {
+ if (!IS_ERR(ct[i].ct_thread))
+ kthread_stop(ct[i].ct_thread);
+ }
mutex_destroy(&cv.cv_mtx);
return rc;
@@ -372,6 +396,12 @@ splat_condvar_test4(struct file *file, void *arg)
/* Wake everything for the failure case */
cv_broadcast(&cv.cv_condvar);
cv_destroy(&cv.cv_condvar);
+
+ /* wait for threads to exit */
+ for (i = 0; i < SPLAT_CONDVAR_TEST_COUNT; i++) {
+ if (!IS_ERR(ct[i].ct_thread))
+ kthread_stop(ct[i].ct_thread);
+ }
mutex_destroy(&cv.cv_mtx);
return rc;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-21 06:34:00 +0000