Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758447AbYC0P1L (ORCPT ); Thu, 27 Mar 2008 11:27:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754517AbYC0P04 (ORCPT ); Thu, 27 Mar 2008 11:26:56 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:60308 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754017AbYC0P0z (ORCPT ); Thu, 27 Mar 2008 11:26:55 -0400 Date: Thu, 27 Mar 2008 16:26:09 +0100 From: Ingo Molnar To: Thomas Gleixner Cc: Andrew Morton , Christian Kujau , LKML , Markus Rehbach , "Rafael J. Wysocki" Subject: Re: 2.6.25-rc6: BUG: unable to handle kernel NULL pointer dereference Message-ID: <20080327152609.GA5406@elte.hu> References: <20080325233357.17d6ac41.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1227 Lines: 35 * Thomas Gleixner wrote: > On Tue, 25 Mar 2008, Andrew Morton wrote: > > > Code: 53 c0 e8 20 08 fc ff c1 e3 02 8b 14 33 89 54 24 20 8b 44 24 20 85 c0 75 10 eb 51 8b 12 89 54 24 20 8b 44 24 20 85 c0 74 43 8b 02 <0f> 18 00 90 8d 5a d8 39 6b 34 75 e4 8b 7c 24 0c 39 7b 30 75 db > > It faults in a prefetch. > > > Markus reported what looks to be the same thing here: > > http://lkml.org/lkml/2008/3/21/202 and it's already in the regresison list. > > Same here. And both are AMD X2 early stepping machines. > > > I guess you've confirmed that this wasn't a mystery > > once-off-on-that-machine. > > > > I can't think what we did to cause this. > > I had a lengthy bug decoding session with Ingo and we found the root > cause: > > A dropped workaround for the prefetch bug in early X2s and > Opterons. Patch below. can also be tested by picking up x86.git/latest, which has this patch included: http://people.redhat.com/mingo/x86.git/README Ingo -- 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/