From: Darrick J. Wong <djwong@kernel.org>
Date: Wed, 20 Dec 2023 16:53:46 +0000 (-0800)
Subject: xfs_scrub: handle spurious wakeups in scan_fs_tree
X-Git-Tag: v6.6.0~5^2~3
X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=817d1b67b6da0a1e2ac94c73ac12fcdb10be1d1e;p=xfsprogs-dev.git

xfs_scrub: handle spurious wakeups in scan_fs_tree

Coverity reminded me that the pthread_cond_wait can wake up and return
without the predicate variable (sft.nr_dirs > 0) actually changing.
Therefore, one has to retest the condition after each wakeup.

Coverity-id: 1554280
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---

diff --git a/scrub/vfs.c b/scrub/vfs.c
index 577eb6dc3..3c1825a75 100644
--- a/scrub/vfs.c
+++ b/scrub/vfs.c
@@ -263,7 +263,7 @@ scan_fs_tree(
 	 * about to tear everything down.
 	 */
 	pthread_mutex_lock(&sft.lock);
-	if (sft.nr_dirs)
+	while (sft.nr_dirs > 0)
 		pthread_cond_wait(&sft.wakeup, &sft.lock);
 	assert(sft.nr_dirs == 0);
 	pthread_mutex_unlock(&sft.lock);