From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id C16B39000C2 for ; Fri, 8 Jul 2011 01:14:13 -0400 (EDT) Received: by qwa26 with SMTP id 26so1092121qwa.14 for ; Thu, 07 Jul 2011 22:14:12 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: Date: Fri, 8 Jul 2011 14:14:09 +0900 Message-ID: Subject: Re: NULL poniter dereference in isolate_lru_pages 2.6.39.1 From: Minchan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Chris Pearson Cc: linux-mm@kvack.org, Andrea Arcangeli On Fri, Jul 8, 2011 at 12:53 AM, Chris Pearson wrote: > see attached screenshots > > NULL pointer dereference at 8 > > isolate_lru_pages > shrink_inactive_list > __lookup_tag > shrink_zone > shrink_slab > kswapd > zone_reclaim > > These are from 3 different servers in the past week since we upgraded > a few hundred of them to 2.6.39.1. =C2=A0 =C2=A0They're under a steady fe= w MB/s > of net and disk I/O load. > > We have the following /proc adjustments: > > kernel.shmmax =3D 135217728 > fs.file-max =3D 65535 > vm.swappiness =3D 10 > vm.min_free_kbytes =3D 65535 > I didn't have see such BUG until now. Could you tell me which point is isolate_lru_pages + 0x225? You can get it with addr2line -e vmlinux -i ffffffff8108ed15 or gdb. The culprit I think is page_count. A month ago, Andrea pointed out and sent the patch but it seems it isn't stable tree. Could you test below patch? https://patchwork.kernel.org/patch/857442/ --=20 Kind regards, Minchan Kim -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org