From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753614Ab2L1Nnd (ORCPT ); Fri, 28 Dec 2012 08:43:33 -0500 Received: from mxout2.iskon.hr ([213.191.128.81]:47985 "EHLO mxout2.iskon.hr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753393Ab2L1Nnc (ORCPT ); Fri, 28 Dec 2012 08:43:32 -0500 X-Remote-IP: 213.191.128.133 Date: Fri, 28 Dec 2012 14:43:24 +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: Zhouping Liu CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ingo Molnar , Johannes Weiner , mgorman@suse.de, hughd@google.com, Andrea Arcangeli , Hillf Danton , sedat.dilek@gmail.com References: <1828895463.36547216.1356662710202.JavaMail.root@redhat.com> <50DD5FD9.2080303@redhat.com> In-Reply-To: <50DD5FD9.2080303@redhat.com> X-Spam-Score: ## Message-ID: <50DDA1FC.8030608@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: 20121228 #8908331, check: 20121228 clean X-SpamTest-Envelope-From: zlatko.calusic@iskon.hr X-SpamTest-Group-ID: 00000000 X-SpamTest-Info: Profiles 40824 [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 10:01, Zhouping Liu wrote: > On 12/28/2012 10:45 AM, Zhouping Liu wrote: >>> Thank you for the report Zhouping! >>> >>> Would you be so kind to test the following patch and report results? >>> Apply the patch to the latest mainline. >> Hello Zlatko, >> >> I have tested the below patch(applied it on mainline directly), >> but IMO, I'd like to say it maybe don't fix the issue completely. > > Hi Zlatko, > > I re-tested it on another machine, which has 60+ Gb RAM and 4 numa nodes, > without your patch, it's easy to reproduce the 'NULL pointer' error, > after applying your patch, I couldn't reproduce the issue any more. > > depending on the above, it implied that your patch fixed the issue. > Yes, that's exactly what I expected. Just wanted to doublecheck this time. Live and learn. ;) > but in my last mail, I tested it on two machines, which caused hung task > with your patch, > so I'm confusing is it your patch block some oom-killer performance? if > it's not, your patch is good for me. > From what I know, the patch shouldn't have much influence on the oom killer, if any. But, as all those subsystems are closely interconnected, both oom & vmscan code is mm after all, there could be some interference. Is the hung-task issue repeatable? -- Zlatko