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authorJan Kara <jack@suse.cz>2016-09-19 14:44:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-09-19 15:36:17 -0700
commit12703dbfeb15402260e7554d32a34ac40c233990 (patch)
treedaff806026a436ba9a359606c8eb580a9d9a7632 /fs/notify/notification.c
parentd5bf141893880f7283fe97e1812c58ff22c8f9a5 (diff)
downloadlinux-12703dbfeb15402260e7554d32a34ac40c233990.tar.gz
fsnotify: add a way to stop queueing events on group shutdown
Implement a function that can be called when a group is being shutdown
to stop queueing new events to the group.  Fanotify will use this.

Fixes: 5838d4442bd5 ("fanotify: fix double free of pending permission events")
Link: http://lkml.kernel.org/r/1473797711-14111-2-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/notify/notification.c')
-rw-r--r--fs/notify/notification.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/notify/notification.c b/fs/notify/notification.c
index a95d8e037aeb..3d76e65ff84f 100644
--- a/fs/notify/notification.c
+++ b/fs/notify/notification.c
@@ -82,7 +82,8 @@ void fsnotify_destroy_event(struct fsnotify_group *group,
  * Add an event to the group notification queue.  The group can later pull this
  * event off the queue to deal with.  The function returns 0 if the event was
  * added to the queue, 1 if the event was merged with some other queued event,
- * 2 if the queue of events has overflown.
+ * 2 if the event was not queued - either the queue of events has overflown
+ * or the group is shutting down.
  */
 int fsnotify_add_event(struct fsnotify_group *group,
 		       struct fsnotify_event *event,
@@ -96,6 +97,11 @@ int fsnotify_add_event(struct fsnotify_group *group,
 
 	mutex_lock(&group->notification_mutex);
 
+	if (group->shutdown) {
+		mutex_unlock(&group->notification_mutex);
+		return 2;
+	}
+
 	if (group->q_len >= group->max_events) {
 		ret = 2;
 		/* Queue overflow event only if it isn't already queued */