From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: Re: [PATCH] cgroup: missing rcu read lock around task_css_set Date: Mon, 03 Mar 2014 17:48:19 -0500 Message-ID: <531506B3.5030004@oracle.com> References: <1393729211-937-1-git-send-email-sasha.levin@oracle.com> <20140303223327.GB26523@mtj.dyndns.org> <5315057F.3030602@oracle.com> <20140303224505.GE26523@mtj.dyndns.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140303224505.GE26523@mtj.dyndns.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Tejun Heo Cc: lizefan@huawei.com, containers@lists.linux-foundation.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org On 03/03/2014 05:45 PM, Tejun Heo wrote: > On Mon, Mar 03, 2014 at 05:43:11PM -0500, Sasha Levin wrote: >> On 03/03/2014 05:33 PM, Tejun Heo wrote: >>> On Sat, Mar 01, 2014 at 10:00:11PM -0500, Sasha Levin wrote: >>>> rcu read lock should be held when calling and working with task_css_set. >>>> >>>> This patch also fixes a related lockdep warning. >>> >>> Hmmm... PF_EXITING should be visible at that point and cset can't >>> change anymore. We prolly need to update lockdep annotation rather >>> than adding spurious rcu locking around it. Against which branch is >>> it? Can you please post the lockdep warning? >> >> I see it on -next. > > I think the right thing to do is using task_css_set_check() with > PF_EXITING check and add comment explaining that cset can no longer > change. Can you please write up a patch? Sure! Thanks, Sasha