On Tue, Oct 31, 2017 at 11:33 AM, Jan Kara <jack@xxxxxxx> wrote: > When fsnotify_add_mark_locked() fails it cleans up the mark it was > adding. Since the mark is already visible in group's list, we should > protect update of mark->flags with mark->lock. I'm not aware of any real > issues this could cause (since we also hold group->mark_mutex) but > better be safe and obey locking rules properly. > > Signed-off-by: Jan Kara <jack@xxxxxxx> Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx> IMO, even though this does not fix a concrete bug, if it's worth fixing in upstream, it's worth fixing in stable. A future stable fix may either make this into a concrete bug or just be harder to apply. So I suggest to add the Fixes: and Cc: stable tags. Greg, Do you agree with this reasoning? > --- > fs/notify/mark.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/fs/notify/mark.c b/fs/notify/mark.c > index 9991f8826734..47a827975b58 100644 > --- a/fs/notify/mark.c > +++ b/fs/notify/mark.c > @@ -599,9 +599,11 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark, struct inode *inode, > > return ret; > err: > + spin_lock(&mark->lock); > mark->flags &= ~(FSNOTIFY_MARK_FLAG_ALIVE | > FSNOTIFY_MARK_FLAG_ATTACHED); > list_del_init(&mark->g_list); > + spin_unlock(&mark->lock); > atomic_dec(&group->num_marks); > > fsnotify_put_mark(mark); > -- > 2.12.3 >
