[ubuntu-hardened] Kernel Panic with SELinux and NFS?

[Jeff Schroeder]

On Mon, Apr 13, 2009 at 11:53 AM, Darren McGuicken
<mailing-ubuntu-hardened at fernseed.info> wrote:
> Hi Jeff,
>
> * Jeff Schroeder (jeffschroed at gmail.com) wrote:
>> > On Mon, Apr 13, 2009 at 12:28:44PM +0100, Darren McGuicken wrote:
>> >> * Kees Cook (kees at ubuntu.com) wrote:
>> >> > On Sun, Apr 12, 2009 at 10:41:00PM +0100, Darren McGuicken wrote:
>> >> > > Hardy server without SELinux, sharing files over NFSv4, Jaunty
>> >> > > beta on my laptop with SELinux enabled == Kernel Panic and hard
>> >> > > lock (on the server!) when accessing files on the NFS share...
>> >> > > Who on earth do I raise the bug report to?
>> >> >
>> >> > If you can reduce it to a series of steps that is easy to
>> >> > reproduce, the best place by far would to be to open a Launchpad
>> >> > bug report against "linux".  I recommend using the "ubuntu-bug
>> >> > linux" command as that will attach various commonly-requested
>> >> > files, etc.
>> >>
>> >> That might be tricky, the server in question runs as my primary
>> >> mail and web server so randomly crashing it isn't really an option.
>>
>> If you would be willing to crash the server once more, you could do
>> this: ... Then when the the problem happens again you should get a
>> vmcore file.
>
> I'm willing to give this a shot (for the good of the community if not my
> server health :->).  I'll schedule some downtime for this weekend, stop
> anything that might lead to data loss, and see if I can recreate once
> more.

Great thanks Darren! In intrepid+ they automated a lot of the
crashdump setup with a metapackage named "linux-crashdump". There is
some rough documentation here:
https://wiki.ubuntu.com/KernelTeam/CrashdumpRecipe

You might have to boot into the crash kernel and manually copy
/proc/vmcore to /var/log. Make sure to also add "kernel.sysrq = 11" to
/etc/sysctl.conf. If the system is hard hung you might just send a
SysRQ c to force a crashdump. The line that says "echo c >
/proc/sysrq-trigger" on that link is the exact same thing. If you want
to hop onto #ubuntu-kernel on IRC and ping SEJeff I'll try to walk you
through some of this.

-- 
Jeff Schroeder

Don't drink and derive, alcohol and analysis don't mix.
http://www.digitalprognosis.com