From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753193Ab1HHSHl (ORCPT ); Mon, 8 Aug 2011 14:07:41 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41913 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751361Ab1HHSHl (ORCPT ); Mon, 8 Aug 2011 14:07:41 -0400 Date: Mon, 8 Aug 2011 19:07:35 +0100 From: Ben Hutchings To: Greg KH Cc: linux-kernel@vger.kernel.org, stable@kernel.org, Trond Myklebust , akpm@linux-foundation.org, torvalds@linux-foundation.org, stable-review@kernel.org, alan@lxorguk.ukuu.org.uk Message-ID: <20110808180735.GD29924@decadent.org.uk> References: <20110806000249.573906795@clark.kroah.org> <1312738681.2591.1024.camel@deadeye> <20110808170300.GA27419@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110808170300.GA27419@suse.de> User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: ben@decadent.org.uk Subject: Re: [Stable-review] [07/55] SUNRPC: Fix a race between work-queue and rpc_killall_tasks X-SA-Exim-Version: 4.2.1 (built Mon, 22 Mar 2010 06:51:10 +0000) X-SA-Exim-Scanned: Yes (on shadbolt.decadent.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 08, 2011 at 10:03:00AM -0700, Greg KH wrote: > On Sun, Aug 07, 2011 at 06:38:01PM +0100, Ben Hutchings wrote: > > On Fri, 2011-08-05 at 17:01 -0700, Greg KH wrote: > > > 2.6.32-longterm review patch. If anyone has any objections, please let us know. > > > > > > ------------------ > > > > > > From: Trond Myklebust > > > > > > commit b55c59892e1f3b6c7d4b9ccffb4263e1486fb990 upstream. > > > > > > Since rpc_killall_tasks may modify the rpc_task's tk_action field > > > without any locking, we need to be careful when dereferencing it. > > [...] > > > > This isn't nearly careful enough to avoid races. You must at least use > > the ACCESS_ONCE macro, otherwise the compiler can just optimise away the > > local variable this introduces. > > Well, that's an upstream issue as well, right? Not much I can do here > in the stable updates :) Right, but if it doesn't fix a bug then it is not suitable for stable. Ben. -- Ben Hutchings We get into the habit of living before acquiring the habit of thinking. - Albert Camus