From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754012AbYKFVRI (ORCPT ); Thu, 6 Nov 2008 16:17:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751353AbYKFVQz (ORCPT ); Thu, 6 Nov 2008 16:16:55 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:42035 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751042AbYKFVQy (ORCPT ); Thu, 6 Nov 2008 16:16:54 -0500 Date: Thu, 6 Nov 2008 22:16:39 +0100 From: Ingo Molnar To: Jeremy Fitzhardinge Cc: Ian Campbell , "Christopher S. Aker" , xen devel , Jan Beulich , Linux Kernel Mailing List Subject: Re: [Xen-devel] 2.6.27 - SMP enabled, but only 1 CPU Message-ID: <20081106211639.GA24579@elte.hu> References: <48F3BC99.5040409@theshore.net> <490F5F50.7020704@theshore.net> <4910AD00.7040605@theshore.net> <4911BC52.7040905@theshore.net> <1225994697.12607.837.camel@zakaz.uk.xensource.com> <49134257.4000404@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49134257.4000404@goop.org> User-Agent: Mutt/1.5.18 (2008-05-17) 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,DNS_FROM_SECURITYSAGE autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] 0.0 DNS_FROM_SECURITYSAGE RBL: Envelope sender in blackholes.securitysage.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jeremy Fitzhardinge wrote: > Ian Campbell wrote: >> On Wed, 2008-11-05 at 10:31 -0500, Christopher S. Aker wrote: >> >>> 2.6.28-rc3 - Brought up 1 CPUs, eventually dies with: >>> http://p.linode.com/1408 >>> >> >> I've been seeing this too. I bisected it down to: >> >> ab00fee30cddf975200b3c97aef25bea144a0d89 is first bad commit >> commit ab00fee30cddf975200b3c97aef25bea144a0d89 >> Author: Jan Beulich >> Date: Thu Oct 30 10:37:21 2008 +0000 >> i386/PAE: fix pud_page() >> Impact: cleanup >> To the unsuspecting user it is quite annoying >> that this broken and >> inconsistent with x86-64 definition still exists. >> Signed-off-by: Jan Beulich >> >> Signed-off-by: Ingo Molnar >> :040000 040000 3b49a9d3792e9f02dd799ad4deb69922d2a085d0 >> f0136498ef53b36172dca595f11a784f43bebcea M arch >> >> It's late so figuring out how it broke can wait for tomorrow. >> >> The interesting bit from the link given is below. >> > > Ah, OK. > > Ingo, Jan: > > Did this patch actually fix anything, or was it just a cleanup? It > seems to have broken 32-bit Xen in some way, so if its just a cleanup it > would be best to drop it until we've worked out what's going on. no, it was pure cleanup. The impact line shows this: >> Impact: cleanup a "cleanup" impact line is only added if the change is not intended to have any side-effects whatsoever. We can drop it but it would be really nice to figure out what's going on. In a very quick late-night look i cannot see anything particularly weird about it, but based on the type of changes it does there are three leading candidates: lost high 32 bits, zero extend problem, or incorrect types. Ingo