diff options
| author | Venky Shankar <vshankar@redhat.com> | 2016-01-27 17:04:18 +0530 |
|---|---|---|
| committer | Venky Shankar <vshankar@redhat.com> | 2016-01-28 05:29:08 -0800 |
| commit | f5ff11159544aa16b44965a0ce4500e9c615895d (patch) | |
| tree | 8ad871583047bcbc831aab2b220d49eb711080d6 | |
| parent | a816cc5124951a2cbe57d2bd95b6690e766c57a7 (diff) | |
features / bitrot: Prevent spurious pthread_cond_wait() wakeup
Backport of http://review.gluster.org/13302
pthread_cond_wait() is prone to spurious wakeups and it's utmost
necessarry to check a boolean predicate for thread continuation.
See man(3) pthread_cond_wait() for details.
The following is done in bitrot scrubber:
if (list_empty (&fsscrub->scrublist))
pthread_cond_wait (&fsscrub->cond, &fsscrub->mutex);
followed by:
list_first_entry (&fsscrub->scrublist, ...)
A spurious wakeup from pthread_cond_wait() with the absence of
list_empty() check causes list_first_entry() to return garbage.
BUG: 1302199
Change-Id: I60151eabb8af257a35acd8e7c117876388166a0e
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.org/13307
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Smoke: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
| -rw-r--r-- | xlators/features/bit-rot/src/bitd/bit-rot-scrub.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/xlators/features/bit-rot/src/bitd/bit-rot-scrub.c b/xlators/features/bit-rot/src/bitd/bit-rot-scrub.c index 9f865f121c7..47d1d262b5f 100644 --- a/xlators/features/bit-rot/src/bitd/bit-rot-scrub.c +++ b/xlators/features/bit-rot/src/bitd/bit-rot-scrub.c @@ -1041,7 +1041,7 @@ _br_scrubber_find_scrubbable_entry (struct br_scrubber *fsscrub, br_child_t *firstchild = NULL; while (1) { - if (list_empty (&fsscrub->scrublist)) + while (list_empty (&fsscrub->scrublist)) pthread_cond_wait (&fsscrub->cond, &fsscrub->mutex); firstchild = NULL; |