Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752031AbaBODiA (ORCPT ); Fri, 14 Feb 2014 22:38:00 -0500 Received: from szxga01-in.huawei.com ([119.145.14.64]:11044 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751582AbaBODh6 (ORCPT ); Fri, 14 Feb 2014 22:37:58 -0500 Message-ID: <52FEE10C.7010101@huawei.com> Date: Sat, 15 Feb 2014 11:37:48 +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: , Subject: Re: [PATCH cgroup/for-3.14-fixes] cgroup: update cgroup_enable_task_cg_lists() to grab siglock References: <20140213182931.GB17608@htj.dyndns.org> In-Reply-To: <20140213182931.GB17608@htj.dyndns.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.18.230] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014/2/14 2:29, Tejun Heo wrote: > Currently, there's nothing preventing cgroup_enable_task_cg_lists() > from missing set PF_EXITING and race against cgroup_exit(). Depending > on the timing, cgroup_exit() may finish with the task still linked on > css_set leading to list corruption. Fix it by grabbing siglock in > cgroup_enable_task_cg_lists() so that PF_EXITING is guaranteed to be > visible. > > This whole on-demand cg_list optimization is extremely fragile and has > ample possibility to lead to bugs which can cause things like > once-a-year oops during boot. I'm wondering whether the better > approach would be just adding "cgroup_disable=all" handling which > disables the whole cgroup rather than tempting fate with this > on-demand craziness. > > Signed-off-by: Tejun Heo > Cc: stable@vger.kernel.org Acked-by: Li Zefan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/