Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757698AbZGMX7f (ORCPT ); Mon, 13 Jul 2009 19:59:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757674AbZGMX7f (ORCPT ); Mon, 13 Jul 2009 19:59:35 -0400 Received: from mx2.redhat.com ([66.187.237.31]:54331 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757629AbZGMX7e (ORCPT ); Mon, 13 Jul 2009 19:59:34 -0400 Date: Tue, 14 Jul 2009 01:56:12 +0200 From: Oleg Nesterov To: James Morris Cc: David Howells , Christoph Hellwig , Andrew Morton , "Paul E. McKenney" , Roland McGrath , Stephen Smalley , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 -mm 2/2] current_is_single_threaded: don't use ->mmap_sem Message-ID: <20090713235612.GA4361@redhat.com> References: <20090710014857.GC4723@redhat.com> <20090709212847.GA10238@redhat.com> <20090710013322.GA27719@infradead.org> <25973.1247234862@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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: 1154 Lines: 36 On 07/13, James Morris wrote: > > On Fri, 10 Jul 2009, David Howells wrote: > > > > However we can avoid ->mmap_sem and rely on rcu/barriers: > > > > > > - if we do not see the exiting parent on thread/process list > > > we see the result of list_del_rcu(), in this case we must > > > also see the result of list_add_rcu() which does wmb(). > > > > > > - if we do see the parent but its ->mm == NULL, we need rmb() > > > to make sure we can't miss the child. > > > > > > Signed-off-by: Oleg Nesterov > > > > Acked-by: David Howells > > I gather this stuff is going into -mm ? Yes, this is on top of rework-fix-is_single_threaded.patch Given that David acked these changes, I guess they will go to -mm soon. > Can it be merged via security-testing#next? Please do what you think right, I don't know what will be more convenient to you and Andrew. 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/