From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935014AbXGLQVj (ORCPT ); Thu, 12 Jul 2007 12:21:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758185AbXGLQVa (ORCPT ); Thu, 12 Jul 2007 12:21:30 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:37060 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755933AbXGLQV3 (ORCPT ); Thu, 12 Jul 2007 12:21:29 -0400 Subject: Re: [PATCH] Immunize rcu_dereference() against crazy compiler writers From: Josh Triplett To: paulmck@linux.vnet.ibm.com Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, dipankar@in.ibm.com, akpm@linux-foundation.org In-Reply-To: <20070712010058.GA30869@linux.vnet.ibm.com> References: <20070712010058.GA30869@linux.vnet.ibm.com> Content-Type: text/plain Date: Thu, 12 Jul 2007 09:08:20 -0700 Message-Id: <1184256500.3000.1.camel@josh-work.beaverton.ibm.com> Mime-Version: 1.0 X-Mailer: Evolution 2.6.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2007-07-11 at 18:00 -0700, Paul E. McKenney wrote: > Turns out that compiler writers are a bit more aggressive about optimizing > than one might expect. This patch prevents a number of such optimizations > from messing up rcu_deference(). This is not merely a theoretical > problem, as evidenced by the rmb() in mce_log(). > > Signed-off-by: Paul E. McKenney Acked-by: Josh Triplett - Josh Triplett