From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753295AbcDNHG0 (ORCPT ); Thu, 14 Apr 2016 03:06:26 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:36651 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751762AbcDNHGZ (ORCPT ); Thu, 14 Apr 2016 03:06:25 -0400 Date: Thu, 14 Apr 2016 09:06:23 +0200 From: Michal Hocko To: Tejun Heo Cc: Petr Mladek , cgroups@vger.kernel.org, Cyril Hrubis , linux-kernel@vger.kernel.org, Johannes Weiner Subject: Re: [BUG] cgroup/workques/fork: deadlock when moving cgroups Message-ID: <20160414070623.GC2850@dhcp22.suse.cz> References: <20160413094216.GC5774@pathway.suse.cz> <20160413183309.GG3676@htj.duckdns.org> <20160413192313.GA30260@dhcp22.suse.cz> <20160413193734.GC20142@htj.duckdns.org> <20160413194820.GC30260@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160413194820.GC30260@dhcp22.suse.cz> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 13-04-16 21:48:20, Michal Hocko wrote: [...] > I was thinking about something like flush_per_cpu_work() which would > assert on group_threadgroup_rwsem held for write. I have thought about this some more and I guess this is not limitted to per cpu workers. Basically any flush_work with group_threadgroup_rwsem held for write is dangerous, right? -- Michal Hocko SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [BUG] cgroup/workques/fork: deadlock when moving cgroups Date: Thu, 14 Apr 2016 09:06:23 +0200 Message-ID: <20160414070623.GC2850@dhcp22.suse.cz> References: <20160413094216.GC5774@pathway.suse.cz> <20160413183309.GG3676@htj.duckdns.org> <20160413192313.GA30260@dhcp22.suse.cz> <20160413193734.GC20142@htj.duckdns.org> <20160413194820.GC30260@dhcp22.suse.cz> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20160413194820.GC30260-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tejun Heo Cc: Petr Mladek , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Cyril Hrubis , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Johannes Weiner On Wed 13-04-16 21:48:20, Michal Hocko wrote: [...] > I was thinking about something like flush_per_cpu_work() which would > assert on group_threadgroup_rwsem held for write. I have thought about this some more and I guess this is not limitted to per cpu workers. Basically any flush_work with group_threadgroup_rwsem held for write is dangerous, right? -- Michal Hocko SUSE Labs