From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754684Ab1LMBdm (ORCPT ); Mon, 12 Dec 2011 20:33:42 -0500 Received: from mail-gx0-f174.google.com ([209.85.161.174]:60263 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753971Ab1LMBdl (ORCPT ); Mon, 12 Dec 2011 20:33:41 -0500 Date: Mon, 12 Dec 2011 17:33:34 -0800 From: Tejun Heo To: Frederic Weisbecker Cc: Linus Torvalds , paul@paulmenage.org, rjw@sisk.pl, lizf@cn.fujitsu.com, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, matthltc@us.ibm.com, akpm@linux-foundation.org, oleg@redhat.com, kamezawa.hiroyu@Jp.fujitsu.com Subject: Re: [PATCH UPDATED AGAIN 03/10] threadgroup: extend threadgroup_lock() to cover exit and exec Message-ID: <20111213013334.GC25802@google.com> References: <1320191193-8110-4-git-send-email-tj@kernel.org> <20111124225054.GA14828@google.com> <20111125140136.GC23307@somewhere.redhat.com> <20111127193001.GC4266@google.com> <20111202162753.GA19752@somewhere.redhat.com> <20111205184315.GJ627@google.com> <20111207153046.GC13252@somewhere.redhat.com> <20111207182214.GA7610@google.com> <20111208205055.GB12108@google.com> <20111209234246.GC27173@somewhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111209234246.GC27173@somewhere> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Sat, Dec 10, 2011 at 12:42:53AM +0100, Frederic Weisbecker wrote: > > Okay, narrowed exit path protection down to setting of PF_EXITING > > itself. ->exit() on dangling tasks is a bit weird but I don't think > > it's too bad. Frederic, are you okay with this version? > > Yeah that new scheme that only protects PF_EXITING may look a bit > strange. But I think we are fine. With rcu list traversal, it should > be safe even if a group member is concurrently dropped from the list (in that > case all we check if its PF_EXITING then we give up). And we may > have a concurrent ->exit() but that should be fine too. > > Thanks! > > Acked-by: Frederic Weisbecker Awesome, adding Acked-by, putting it on top of pm-freezer and pushing it out to linux-next. Thank you. -- tejun