From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759427AbXGIWaG (ORCPT ); Mon, 9 Jul 2007 18:30:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755158AbXGIW34 (ORCPT ); Mon, 9 Jul 2007 18:29:56 -0400 Received: from wa-out-1112.google.com ([209.85.146.178]:8273 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755062AbXGIW3z (ORCPT ); Mon, 9 Jul 2007 18:29:55 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=JsLZroXhlYo3fmVS/UinBnKJL0H62GipoCDZ+jy9Gz2il8MTaemphiymtCBFky+I78KHWR804pKnpl2/4FPMqLF36GT2AZhDHdc39RLvgbEPm5zrEbIP1nofCkcXgfEY2ipvcQILP123KOOcWubZpP+QLp9X2uNLNzsbOxi9jUM= Message-ID: <9a8748490707091529j153d7202s47596b78b7aac612@mail.gmail.com> Date: Tue, 10 Jul 2007 00:29:54 +0200 From: "Jesper Juhl" To: "Charles Shannon Hendrix" Subject: Re: BUG: kernel crash report, odd... Cc: linux-kernel@vger.kernel.org In-Reply-To: <9a8748490707091519g3a0a098dx1e9188083c5a74b4@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20070709220848.GA6782@widomaker.com> <9a8748490707091519g3a0a098dx1e9188083c5a74b4@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Forgot a few things, see below... On 10/07/07, Jesper Juhl wrote: > On 10/07/07, Charles Shannon Hendrix wrote: > > > > A system I was using a few minutes ago dumped this to the syslog: > > > > Jul 9 17:50:38 daydream kernel: [76022.613000] BUG: unable to handle > > kernel NUL > > L pointer dereference at virtual address 00000010 > > Jul 9 17:50:38 daydream kernel: [76022.613000] printing eip: > > Jul 9 17:50:38 daydream kernel: [76022.613000] c01ace66 > > Jul 9 17:50:38 daydream kernel: [76022.613000] *pde = 00000000 > > Jul 9 17:50:38 daydream kernel: [76022.613000] Oops: 0000 [#1] > > > > > > There was no other information either before or after. > > > > What I saw was my KDE desktop stopped responding to events. > > > > Machine didn't respond to power switch. > > > > Unfortunately, that's all I know. > > > > In the past when I had bugs like this, I got a fairly extensive kernel > > error message, but this time the above is the only thing I saw. > > > It does look a little short... probably the rest just didn't make it to disk... > > > I have not had kernel bugs like this until I started running 2.6.20 on a > > new Kubuntu install. > > > > Same hardware, but Slackware and my own custom 2.6.19 kernel never > > crashed. > > > Different kernel source version, different configuration, probably > different compiler, Slackware doesn't patch the vanilla kernel - I > believe (k)ubuntu does. All in all that equals a significantly > different kernel binary you have been running in those two cases. > A different userspace could also be the cause. In theory, userspace should never be able to crash the kernel, but in real life bugs happen and sometimes userspace manages to cause a kernel crash. So, a different userspace environment in your new distribution could in theory expose a bug that didn't surface with your previous distribution. > > Is there anything I can do, in case this happens again, to try and > > capture more information? > > > 0. Make sure the kernels loglevel is set so that you get all messages. > 0.5. Perhaps increase the size of the kernels log buffer (the LOG_BUF_SHIFT config option) > 1. Make sure syslog is setup to capture all kernel messages, both > errors, warnings, notices, debug messages etc. > > 2. If you can, check output of 'dmesg' instead of just what made it to syslog. > > 3. If you have a second PC, setup serial console or netconsole to > capture kernel messages on that second box. This can sometimes capture > messages that don't make it to disk. > > 4. Build a custom kernel with some (or all) of the debug options under > the Kernel Hacking menu enabled. > > 5. Even when the system hangs you may in some cases be able to get > some info (or just sync the disks and do a reboot) via magic sysrq. > -- Jesper Juhl Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please http://www.expita.com/nomime.html