Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753568AbWKFU7P (ORCPT ); Mon, 6 Nov 2006 15:59:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753612AbWKFU7P (ORCPT ); Mon, 6 Nov 2006 15:59:15 -0500 Received: from gate.crashing.org ([63.228.1.57]:35764 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S1753568AbWKFU7N (ORCPT ); Mon, 6 Nov 2006 15:59:13 -0500 Subject: Re: PATCH? hrtimer_wakeup: fix a theoretical race wrt rt_mutex_slowlock() From: Benjamin Herrenschmidt To: Steven Rostedt Cc: Linus Torvalds , Oleg Nesterov , Thomas Gleixner , Andrew Morton , linux-kernel@vger.kernel.org In-Reply-To: References: <20061105193457.GA3082@oleg> <1162803471.28571.303.camel@localhost.localdomain> Content-Type: text/plain Date: Tue, 07 Nov 2006 07:53:53 +1100 Message-Id: <1162846433.28571.341.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.8.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 576 Lines: 24 On Mon, 2006-11-06 at 07:35 -0500, Steven Rostedt wrote: > It is relevant. In powerpc, can one write happen before another write? > > > x = 1; > barrier(); (only compiler barrier) > b = 2; > > > And have CPU 2 see b=2 before seeing x=1? Yes. Definitely. > If so, then I guess this is indeed a bug on powerpc. Ben. - 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/