From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759572Ab3FNB51 (ORCPT ); Thu, 13 Jun 2013 21:57:27 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:49445 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759431Ab3FNB5X (ORCPT ); Thu, 13 Jun 2013 21:57:23 -0400 Message-ID: <51BA77A6.70404@huawei.com> Date: Fri, 14 Jun 2013 09:53:42 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 MIME-Version: 1.0 To: Andrew Morton CC: Tejun Heo , Glauber Costa , KAMEZAWA Hiroyuki , Johannes Weiner , LKML , Cgroups , , Michal Hocko Subject: [PATCH v4 1/9] Revert "memcg: avoid dangling reference count in creation failure." References: <51BA7794.2000305@huawei.com> In-Reply-To: <51BA7794.2000305@huawei.com> Content-Type: text/plain; charset="GB2312" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.135.68.215] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michal Hocko This reverts commit e4715f01be697a3730c78f8ffffb595591d6a88c 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. Cc: # 3.9+ Signed-off-by: Michal Hocko Signed-off-by: Li Zefan Acked-by: KAMEZAWA Hiroyuki --- mm/memcontrol.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 2e851f4..0bacc0d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6332,8 +6332,6 @@ 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; } -- 1.8.0.2