From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752110Ab3HUCXu (ORCPT ); Tue, 20 Aug 2013 22:23:50 -0400 Received: from szxga01-in.huawei.com ([119.145.14.64]:13332 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751533Ab3HUCXt (ORCPT ); Tue, 20 Aug 2013 22:23:49 -0400 Message-ID: <52142464.1060603@huawei.com> Date: Wed, 21 Aug 2013 10:22:28 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Tejun Heo CC: LKML , Cgroups Subject: [PATCH] cpuset: fix a regression in validating config change 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 It's not allowed to clear masks of a cpuset if there're tasks in it, but it's broken: # mkdir /cgroup/sub # echo 0 > /cgroup/sub/cpuset.cpus # echo 0 > /cgroup/sub/cpuset.mems # echo $$ > /cgroup/sub/tasks # echo > /cgroup/sub/cpuset.cpus (should fail) This bug was introduced by commit 88fa523bff295f1d60244a54833480b02f775152 ("cpuset: allow to move tasks to empty cpusets"). Signed-off-by: Li Zefan --- kernel/cpuset.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 0b5b9a3..70ab3fd 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -425,6 +425,8 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial) struct cgroup_subsys_state *css; struct cpuset *c, *par; int ret; + bool make_cpus_empty; + bool make_mems_empty; rcu_read_lock(); @@ -464,12 +466,15 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial) /* * Cpusets with tasks - existing or newly being attached - can't - * have empty cpus_allowed or mems_allowed. + * be changed to have empty cpus_allowed or mems_allowed. */ ret = -ENOSPC; + make_cpus_empty = !cpumask_empty(cur->cpus_allowed) && + cpumask_empty(trial->cpus_allowed); + make_mems_empty = !nodes_empty(cur->mems_allowed) && + nodes_empty(trial->mems_allowed); if ((cgroup_task_count(cur->css.cgroup) || cur->attach_in_progress) && - (cpumask_empty(trial->cpus_allowed) && - nodes_empty(trial->mems_allowed))) + (make_cpus_empty || make_mems_empty)) goto out; ret = 0; -- 1.8.0.2