5.10-stable review patch. If anyone has any objections, please let me know.
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From: Amir Goldstein amir73il@gmail.com
[ Upstream commit 4396a73115fc8739083536162e2228c0c0c3ed1a ]
Fix a leak in s_fsnotify_connectors counter in case of a race between concurrent add of new fsnotify mark to an object.
The task that lost the race fails to drop the counter before freeing the unused connector.
Following umount() hangs in fsnotify_sb_delete()/wait_var_event(), because s_fsnotify_connectors never drops to zero.
Fixes: ec44610fe2b8 ("fsnotify: count all objects with attached connectors") Reported-by: Murphy Zhou jencce.kernel@gmail.com Link: https://lore.kernel.org/linux-fsdevel/20210907063338.ycaw6wvhzrfsfdlp@xzhoux... Signed-off-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/notify/mark.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/fs/notify/mark.c b/fs/notify/mark.c index 796946eb0c2e2..bea106fac0901 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -531,6 +531,7 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp, /* Someone else created list structure for us */ if (inode) fsnotify_put_inode_ref(inode); + fsnotify_put_sb_connectors(conn); kmem_cache_free(fsnotify_mark_connector_cachep, conn); }