Commit 1c17d18e authored by Yan Zheng's avatar Yan Zheng Committed by Linus Torvalds

A potential bug in inotify_user.c

Following comment is at fs/inotify_user.c:287
/* coalescing: drop this event if it is a dupe of the previous */

I think the previous event in the comment should be the last event in the
link list.  But inotify_dev_get_event return the first event in the list.
In addition, it doesn't check whether the list is empty

Signed-off-by: Yan Zheng<yanzheng@21cn.com>
Acked-by: default avatarRobert Love <rlove@rlove.org>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 19c561a6
......@@ -247,6 +247,19 @@ inotify_dev_get_event(struct inotify_device *dev)
return list_entry(dev->events.next, struct inotify_kernel_event, list);
}
/*
* inotify_dev_get_last_event - return the last event in the given dev's queue
*
* Caller must hold dev->ev_mutex.
*/
static inline struct inotify_kernel_event *
inotify_dev_get_last_event(struct inotify_device *dev)
{
if (list_empty(&dev->events))
return NULL;
return list_entry(dev->events.prev, struct inotify_kernel_event, list);
}
/*
* inotify_dev_queue_event - event handler registered with core inotify, adds
* a new event to the given device
......@@ -273,7 +286,7 @@ static void inotify_dev_queue_event(struct inotify_watch *w, u32 wd, u32 mask,
put_inotify_watch(w); /* final put */
/* coalescing: drop this event if it is a dupe of the previous */
last = inotify_dev_get_event(dev);
last = inotify_dev_get_last_event(dev);
if (last && last->event.mask == mask && last->event.wd == wd &&
last->event.cookie == cookie) {
const char *lastname = last->name;
......
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