Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754853Ab2BVSKX (ORCPT ); Wed, 22 Feb 2012 13:10:23 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54351 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751042Ab2BVSKV (ORCPT ); Wed, 22 Feb 2012 13:10:21 -0500 Date: Wed, 22 Feb 2012 19:03:27 +0100 From: Oleg Nesterov To: Frederic Weisbecker Cc: "Paul E. McKenney" , Mandeep Singh Baines , Tejun Heo , Li Zefan , LKML , Andrew Morton Subject: Re: [PATCH 2/2] cgroup: Walk task list under tasklist_lock in cgroup_enable_task_cg_list Message-ID: <20120222180327.GA11044@redhat.com> References: <1328668647-24125-1-git-send-email-fweisbec@gmail.com> <1328668647-24125-3-git-send-email-fweisbec@gmail.com> <20120221222343.GU3090@google.com> <20120222005525.GC13403@somewhere.redhat.com> <20120222011934.GX2375@linux.vnet.ibm.com> <20120222013339.GG13403@somewhere.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120222013339.GG13403@somewhere.redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1031 Lines: 28 Hi. Sorry, currently I do not have the time to even read this discussion, just one note, On 02/22, Frederic Weisbecker wrote: > > On Tue, Feb 21, 2012 at 05:19:34PM -0800, Paul E. McKenney wrote: > > On Wed, Feb 22, 2012 at 01:55:28AM +0100, Frederic Weisbecker wrote: > > > On Tue, Feb 21, 2012 at 02:23:43PM -0800, Mandeep Singh Baines wrote: > > > > Frederic Weisbecker (fweisbec@gmail.com) wrote: > > > > > Walking through the tasklist in cgroup_enable_task_cg_list() inside > > > > > an RCU read side critical section is not enough because: > > > > > > > > > > - RCU is not (yet) safe against while_each_thread() Yes. Except I'd say it is while_each_thread() who is not safe ;) Please do not take this into account. This should be fixed, I hope to send the fix "soon". Oleg. -- 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/