inotify: do not leak inode marks in inotify_add_watch
inotify_add_watch had a couple of problems. The biggest being that if
inotify_add_watch was called on the same inode twice (to update or change the
event mask) a refence was taken on the original inode mark by
fsnotify_find_mark_entry but was not being dropped at the end of the
inotify_add_watch call. Thus if inotify_rm_watch was called although the mark
was removed from the inode, the refcnt wouldn't hit zero and we would leak
memory.
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index 1a870f9..aff4214 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -463,9 +463,6 @@
goto out_err;
spin_lock(&group->inotify_data.idr_lock);
- /* if entry is added to the idr we keep the reference obtained
- * through fsnotify_mark_add. remember to drop this reference
- * when entry is removed from idr */
ret = idr_get_new_above(&group->inotify_data.idr, entry,
++group->inotify_data.last_wd,
&ientry->wd);
@@ -476,8 +473,13 @@
goto out_err;
}
atomic_inc(&group->inotify_data.user->inotify_watches);
+
+ /* we put the mark on the idr, take a reference */
+ fsnotify_get_mark(entry);
}
+ ret = ientry->wd;
+
spin_lock(&entry->lock);
old_mask = entry->mask;
@@ -508,7 +510,11 @@
fsnotify_recalc_group_mask(group);
}
- return ientry->wd;
+ /* this either matches fsnotify_find_mark_entry, or init_mark_entry
+ * depending on which path we took... */
+ fsnotify_put_mark(entry);
+
+ return ret;
out_err:
/* see this isn't supposed to happen, just kill the watch */