debugging / fixing kernel panics on ubuntu

[jarod at wilsonet.com (Jarod Wilson)]

On Sunday 29 April 2007 17:27:15 Kristian Hermansen wrote:
> So, I've been having hard panics (caps-lock blinking) on my AMD64
> laptop running Ubuntu Feisty (7.04) more and more frequently since
> January [yes, i was running herd back then].  Now it's at the point
> where I see it every day, sometimes even more than once per day, like
> today :-)  Is there an Ubuntu-style triage method?  I would maybe try
> lkdump to generate a diskdump, but the patches are for 2.6.9, probably
> RHEL4 type machines.  How can I get to the bottom of this?
>
> FYI, I am not using closed source nvidia drivers in my Xorg.conf and
> they are not listed in lsmod, so I don't think it should be attributed
> to nvidia.  Any other ideas are welcomed...thanks!

You may want to check out kdump. Its what Red Hat ships as its standard kernel 
crash dump collection method in RHEL5. The bulk of it is in upstream as of a 
few kernel releases ago. The only caveat for your situation is that x86_64 
relocatable (within memory) kernel support isn't upstream yet, so I believe 
you'll need a separate kernel to kexec into that is set up to run at a 
different memory offset for panic dump purposes.

nb: i386 and ia64 kernels are relocatable, x86_64 patches exist and are in 
RHEL5, but haven't yet been merged in Linus' tree -- may make 2.6.22, ppc64 
is still a work in progress.

A Fedora-specific howto can be found here:

http://fedoraproject.org/wiki/FC6KdumpKexecHowTo

There's also a link there to the upstream project page which could have 
further pointers.

-- 
Jarod Wilson
jarod at wilsonet.com

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