From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx182.postini.com [74.125.245.182]) by kanga.kvack.org (Postfix) with SMTP id D2BF26B002B for ; Fri, 28 Dec 2012 08:43:31 -0500 (EST) Date: Fri, 28 Dec 2012 14:43:24 +0100 From: Zlatko Calusic MIME-Version: 1.0 References: <1828895463.36547216.1356662710202.JavaMail.root@redhat.com> <50DD5FD9.2080303@redhat.com> In-Reply-To: <50DD5FD9.2080303@redhat.com> 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 Sender: owner-linux-mm@kvack.org List-ID: 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 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org