From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751516Ab2L0XvM (ORCPT ); Thu, 27 Dec 2012 18:51:12 -0500 Received: from mxout2.iskon.hr ([213.191.128.81]:38367 "EHLO mxout2.iskon.hr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750891Ab2L0XvK (ORCPT ); Thu, 27 Dec 2012 18:51:10 -0500 X-Remote-IP: 213.191.128.133 Date: Fri, 28 Dec 2012 00:51:01 +0100 From: Zlatko Calusic Organization: Iskon Internet d.d. User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Icedove/17.0 MIME-Version: 1.0 To: sedat.dilek@gmail.com CC: LKML , linux-mm References: <50DCDC21.6080303@iskon.hr> In-Reply-To: Message-ID: <50DCDEE5.9000700@iskon.hr> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: BUG: unable to handle kernel NULL pointer dereference at 0000000000000500 X-Anti-Virus: Kaspersky Anti-Virus for Linux Mail Server 5.6.45/RELEASE, bases: 20121227 #8899382, check: 20121227 clean X-SpamTest-Envelope-From: zlatko.calusic@iskon.hr X-SpamTest-Group-ID: 00000000 X-SpamTest-Info: Profiles 40795 [Dec 28 2012] X-SpamTest-Method: none X-SpamTest-Rate: 0 X-SpamTest-SPF: none X-SpamTest-Status: Not detected X-SpamTest-Status-Extended: not_detected X-SpamTest-Version: SMTP-Filter Version 3.0.0 [0284], KAS30/Release Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28.12.2012 00:42, Sedat Dilek wrote: > On Fri, Dec 28, 2012 at 12:39 AM, Zlatko Calusic > wrote: >> On 28.12.2012 00:30, Sedat Dilek wrote: >>> >>> Hi Zlatko, >>> >>> I am not sure if I hit the same problem as described in this thread. >>> >>> Under heavy load, while building a customized toolchain for the Freetz >>> router project I got a BUG || NULL pointer derefence || kswapd || >>> zone_balanced || pgdat_balanced() etc. (details see my screenshot). >>> >>> I will try your patch from [1] ***only*** on top of my last >>> Linux-v3.8-rc1 GIT setup (post-v3.8-rc1 mainline + some net-fixes). >>> >> >> Yes, that's the same bug. It should be fixed with my latest patch, so I'd >> appreciate you testing it, to be on the safe side this time. There should be >> no difference if you apply it to anything newer than 3.8-rc1, so go for it. >> Thanks! >> > > Not sure how I can really reproduce this bug as one build worked fine > within my last v3.8-rc1 kernel. > I increased the parallel-make-jobs-number from "4" to "8" to stress a > bit harder. > Just building right now... and will report. > > If you have any test-case (script or whatever), please let me/us know. > Unfortunately not, I haven't reproduced it yet on my machines. But it seems that bug will hit only under heavy memory pressure. When close to OOM, or possibly with lots of writing to disk. It's also possible that fragmentation of memory zones could provoke it, that means testing it for a longer time. -- Zlatko