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authorVenky Shankar <vshankar@redhat.com>2016-01-27 17:04:18 +0530
committerVenky Shankar <vshankar@redhat.com>2016-01-28 05:29:08 -0800
commitf5ff11159544aa16b44965a0ce4500e9c615895d (patch)
tree8ad871583047bcbc831aab2b220d49eb711080d6 /xlators/features/bit-rot
parenta816cc5124951a2cbe57d2bd95b6690e766c57a7 (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>
Diffstat (limited to 'xlators/features/bit-rot')
-rw-r--r--xlators/features/bit-rot/src/bitd/bit-rot-scrub.c2
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 9f865f1..47d1d26 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;