From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [Bug #11035] System hangs on 2.6.26-rc8 Date: Fri, 18 Jul 2008 09:11:21 +0200 Message-ID: <20080718071121.GB6875@elte.hu> References: <4878D259.7050403@r000n.net> <487CA8E5.8020208@r000n.net> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <487CA8E5.8020208-ioAbOcnQCpJeoWH0uzbU5w@public.gmane.org> Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Roman Mindalev Cc: "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Thomas Gleixner , Vegard Nossum * Roman Mindalev wrote: > I done bisection. > Result below: > > 8f46924600e30b140445f5b84abe9b80d2fff5fb is first bad commit > commit 8f46924600e30b140445f5b84abe9b80d2fff5fb > Author: Ingo Molnar > Date: Wed Jan 30 13:34:09 2008 +0100 > > x86: enable CONFIG_DEBUG_PAGEALLOC more widely > > make CONFIG_DEBUG_PAGEALLOC universally available. > > CONFIG_HIBERNATION and CONFIG_HUGETLBFS was disabling it, for no > particular reason. as far as i can see you see a lockup under certain circumstances, right? this debug option catches use-after-free and other types of invalid memory accesses. When it catches a bug the kernel most likely crashes and produces a backlog. Because you are in graphical mode that is not visible. This would possibly be debuggable if you set up netconsole logging to another system on a local LAN - see Documentation/networking/netconsole.txt. Vegard - would it be possible to make DEBUG_PAGEALLOC faults single-shot and non-fatal, just like kmemcheck does it? That way people would see a nice kernel message instead of an immediate crash. That means we'd have to find a reliable filter for DEBUG_PAGEALLOC-provoked pagefaults though ... Ingo From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754581AbYGRHLn (ORCPT ); Fri, 18 Jul 2008 03:11:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752697AbYGRHLg (ORCPT ); Fri, 18 Jul 2008 03:11:36 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:49555 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752567AbYGRHLf (ORCPT ); Fri, 18 Jul 2008 03:11:35 -0400 Date: Fri, 18 Jul 2008 09:11:21 +0200 From: Ingo Molnar To: Roman Mindalev Cc: "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Thomas Gleixner , Vegard Nossum Subject: Re: [Bug #11035] System hangs on 2.6.26-rc8 Message-ID: <20080718071121.GB6875@elte.hu> References: <4878D259.7050403@r000n.net> <487CA8E5.8020208@r000n.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <487CA8E5.8020208@r000n.net> 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 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 * Roman Mindalev wrote: > I done bisection. > Result below: > > 8f46924600e30b140445f5b84abe9b80d2fff5fb is first bad commit > commit 8f46924600e30b140445f5b84abe9b80d2fff5fb > Author: Ingo Molnar > Date: Wed Jan 30 13:34:09 2008 +0100 > > x86: enable CONFIG_DEBUG_PAGEALLOC more widely > > make CONFIG_DEBUG_PAGEALLOC universally available. > > CONFIG_HIBERNATION and CONFIG_HUGETLBFS was disabling it, for no > particular reason. as far as i can see you see a lockup under certain circumstances, right? this debug option catches use-after-free and other types of invalid memory accesses. When it catches a bug the kernel most likely crashes and produces a backlog. Because you are in graphical mode that is not visible. This would possibly be debuggable if you set up netconsole logging to another system on a local LAN - see Documentation/networking/netconsole.txt. Vegard - would it be possible to make DEBUG_PAGEALLOC faults single-shot and non-fatal, just like kmemcheck does it? That way people would see a nice kernel message instead of an immediate crash. That means we'd have to find a reliable filter for DEBUG_PAGEALLOC-provoked pagefaults though ... Ingo