From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755493AbYCHPXw (ORCPT ); Sat, 8 Mar 2008 10:23:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752212AbYCHPXm (ORCPT ); Sat, 8 Mar 2008 10:23:42 -0500 Received: from mx1.redhat.com ([66.187.233.31]:48035 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752166AbYCHPXl (ORCPT ); Sat, 8 Mar 2008 10:23:41 -0500 Date: Sat, 8 Mar 2008 10:23:21 -0500 From: Rik van Riel To: Davide Libenzi Cc: Jeff Roberson , Linux Kernel Mailing List , Zach Brown Subject: Re: [PATCH] eventfd signal race in aio_complete() Message-ID: <20080308102321.4527372e@bree.surriel.com> In-Reply-To: References: <20080307161854.E920@desktop> Organization: Red Hat, Inc. X-Mailer: Claws Mail 3.0.2 (GTK+ 2.10.4; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 7 Mar 2008 20:29:20 -0800 (PST) Davide Libenzi wrote: > The second solution/patch simply moves the eventfd_signal() call before > the __aio_put_req() call, but after the event has beed "ringed". > We should be clear to go with the shorter/nicer second solution. Those > patches builds, but I'm not even signing them off till I tested them. If there are no spinlock ordering issues between &ctx->ctx_lock and &ctx->wqh.lock (taken inside eventfd_signal), then the second patch is indeed preferable. Jeff and I did look at that briefly last night, but were not familiar enough with the code to decide whether or not that was safe. -- All rights reversed.