From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764015AbYDVN1g (ORCPT ); Tue, 22 Apr 2008 09:27:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758815AbYDVN13 (ORCPT ); Tue, 22 Apr 2008 09:27:29 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:41191 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757334AbYDVN12 (ORCPT ); Tue, 22 Apr 2008 09:27:28 -0400 Date: Tue, 22 Apr 2008 15:26:14 +0200 From: Ingo Molnar To: Mathieu Desnoyers Cc: akpm@osdl.org, "H. Peter Anvin" , Jeremy Fitzhardinge , Steven Rostedt , "Frank Ch. Eigler" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Fix x86_64 page fault scheduler race Message-ID: <20080422132614.GC7311@elte.hu> References: <20080422132151.GA32120@Krystal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080422132151.GA32120@Krystal> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0001] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Mathieu Desnoyers wrote: > You are right in that x86_64 does not seems to play as safely as > x86_32 on this matter; it uses current->mm. Probably it shouldn't > assume "current" is valid. Actually, I don't see where x86_64 disables > interrupts around __switch_to, so this would seem to be a race > condition. Or have I missed something ? the scheduler disables interrupts around __switch_to(). (x86 does not set __ARCH_WANT_INTERRUPTS_ON_CTXSW) Ingo