Revert "memcg: avoid dangling reference count in creation failure"
authorMichal Hocko <mhocko@suse.cz>
Mon, 8 Jul 2013 23:00:27 +0000 (16:00 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 9 Jul 2013 17:33:24 +0000 (10:33 -0700)
This reverts commit e4715f01be697a.

mem_cgroup_put is hierarchy aware so mem_cgroup_put(memcg) already drops
an additional reference from all parents so the additional
mem_cgrroup_put(parent) potentially causes use-after-free.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Glauber Costa <glommer@openvz.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org> [3.9+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/memcontrol.c

index 64f726599ff06c6319b82c05dc5a93ef17f5fe09..6b73d8657d64ae45bfd0085e6d4111fa417f3337 100644 (file)
@@ -6352,8 +6352,6 @@ mem_cgroup_css_online(struct cgroup *cont)
                 * call __mem_cgroup_free, so return directly
                 */
                mem_cgroup_put(memcg);
-               if (parent->use_hierarchy)
-                       mem_cgroup_put(parent);
        }
        return error;
 }