From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751330AbdHaMKB (ORCPT ); Thu, 31 Aug 2017 08:10:01 -0400 Received: from mx2.suse.de ([195.135.220.15]:34652 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750928AbdHaMKA (ORCPT ); Thu, 31 Aug 2017 08:10:00 -0400 Date: Thu, 31 Aug 2017 14:09:51 +0200 From: Michal Hocko To: Artem Savkov Cc: Thomas Gleixner , "Paul E. McKenney" , LKML , Johannes Weiner , linux-mm@kvack.org Subject: Re: possible circular locking dependency mmap_sem/cpu_hotplug_lock.rw_sem Message-ID: <20170831120951.hqlu2ai5i7hly7nk@dhcp22.suse.cz> References: <20170807140947.nhfz2gel6wytl6ia@shodan.usersys.redhat.com> <20170830141543.qhipikpog6mkqe5b@dhcp22.suse.cz> <20170830154315.sa57wasw64rvnuhe@dhcp22.suse.cz> <20170831111006.i7srs56xki4bjx34@shodan.usersys.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170831111006.i7srs56xki4bjx34@shodan.usersys.redhat.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 31-08-17 13:10:06, Artem Savkov wrote: > Hi Michal, > > On Wed, Aug 30, 2017 at 05:43:15PM +0200, Michal Hocko wrote: > > The previous patch is insufficient. drain_all_stock can still race with > > the memory offline callback and the underlying memcg disappear. So we > > need to be more careful and pin the css on the memcg. This patch > > instead... > > Tried this on top of rc7 and it does fix the splat for me. Thanks for testing! Can I assume your Tested-by? -- Michal Hocko SUSE Labs