Revert "memcg: avoid dangling reference count in creation failure"

This reverts commit e4715f01be.

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>
This commit is contained in:
Michal Hocko 2013-07-08 16:00:27 -07:00 committed by Linus Torvalds
parent 493af57804
commit fa460c2d37

View 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;
}