From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754019AbdEQUYj (ORCPT ); Wed, 17 May 2017 16:24:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59882 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750944AbdEQUYg (ORCPT ); Wed, 17 May 2017 16:24:36 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 353C37F4A5 Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=longman@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 353C37F4A5 Subject: Re: [RFC PATCH v2 07/17] cgroup: Prevent kill_css() from being called more than once To: Tejun Heo References: <1494855256-12558-1-git-send-email-longman@redhat.com> <1494855256-12558-8-git-send-email-longman@redhat.com> <20170517192357.GC942@htj.duckdns.org> Cc: Li Zefan , Johannes Weiner , Peter Zijlstra , Ingo Molnar , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, kernel-team@fb.com, pjt@google.com, luto@amacapital.net, efault@gmx.de From: Waiman Long Organization: Red Hat Message-ID: Date: Wed, 17 May 2017 16:24:32 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170517192357.GC942@htj.duckdns.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Wed, 17 May 2017 20:24:35 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/17/2017 03:23 PM, Tejun Heo wrote: > Hello, > > On Mon, May 15, 2017 at 09:34:06AM -0400, Waiman Long wrote: >> The kill_css() function may be called more than once under the condition >> that the css was killed but not physically removed yet followed by the >> removal of the cgroup that is hosting the css. This patch prevents any >> harmm from being done when that happens. >> >> Signed-off-by: Waiman Long > So, this is a bug fix which isn't really related to this patchset. > I'm applying it to cgroup/for-4.12-fixes w/ stable cc'd. > > Thanks. > Actually, this bug can be easily triggered with the resource domain patch later in the series. I guess it can also happen in the current code base, but I don't have a test that can reproduce it. Regards, Longman