notify: unused event private race
inotify decides if private data it passed to get added to an event was
used by checking list_empty(). But it's possible that the event may
have been dequeued and the private event removed so it would look empty.
The fix is to use the return code from fsnotify_add_notify_event rather
than looking at the list.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/notify/notification.c b/fs/notify/notification.c
index 5213685..74b3cf3 100644
--- a/fs/notify/notification.c
+++ b/fs/notify/notification.c
@@ -171,9 +171,7 @@
struct list_head *list = &group->notification_list;
struct fsnotify_event_holder *last_holder;
struct fsnotify_event *last_event;
-
- /* easy to tell if priv was attached to the event */
- INIT_LIST_HEAD(&priv->event_list);
+ int ret = 0;
/*
* There is one fsnotify_event_holder embedded inside each fsnotify_event.
@@ -194,6 +192,7 @@
if (group->q_len >= group->max_events) {
event = &q_overflow_event;
+ ret = -EOVERFLOW;
/* sorry, no private data on the overflow event */
priv = NULL;
}
@@ -235,7 +234,7 @@
mutex_unlock(&group->notification_mutex);
wake_up(&group->notification_waitq);
- return 0;
+ return ret;
}
/*