From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932150Ab3CLC2z (ORCPT ); Mon, 11 Mar 2013 22:28:55 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:57757 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754709Ab3CLC2x (ORCPT ); Mon, 11 Mar 2013 22:28:53 -0400 Message-ID: <513E92D7.9050903@huawei.com> Date: Tue, 12 Mar 2013 10:28:39 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130215 Thunderbird/17.0.3 MIME-Version: 1.0 To: Tejun Heo CC: Sasha Levin , LKML , Cgroups Subject: [PATCH] cpuset: fix RCU lockdep splat in cpuset_print_task_mems_allowed() 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 Sasha reported a lockdep warning when OOM was triggered. The reason is cgroup_name() should be called with rcu_read_lock() held. Reported-by: Sasha Levin Signed-off-by: Li Zefan --- This fix is for 3.10 --- kernel/cpuset.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/cpuset.c b/kernel/cpuset.c index c55763b..98d458a 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -2599,6 +2599,7 @@ void cpuset_print_task_mems_allowed(struct task_struct *tsk) struct cgroup *cgrp = task_cs(tsk)->css.cgroup; + rcu_read_lock(); spin_lock(&cpuset_buffer_lock); nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN, @@ -2607,6 +2608,7 @@ void cpuset_print_task_mems_allowed(struct task_struct *tsk) tsk->comm, cgroup_name(cgrp), cpuset_nodelist); spin_unlock(&cpuset_buffer_lock); + rcu_read_unlock(); } /* -- 1.8.0.2