[OpenAFS] Re: BUG: unable to handle kernel paging request at 0000000000004f62

Andrew Deason adeason@sinenomine.net
Tue, 17 Dec 2013 22:03:55 -0600

On Tue, 17 Dec 2013 15:02:59 +0000
Jose Manuel dos Santos Calhariz <jose.calhariz@tecnico.ulisboa.pt> wrote:

> I have a virtual machine that since I have upgrade it to Debian wheezy 
> (v7.0), Linux kernel 3.2, it started to give BUG messages.
> This machine runs every night, tar commands to do, backups of the files 
> of AFS.  Usually at the second night I get this BUG messages
> and some of the running tar stops.
> The openafs kernel module is the same version previous and after the 
> upgrade.  So this can be a possible incompatibility between
> kernel 3.2 and openafs 1.6.5., where the kernel 2.6.32 worked fine.

I'm a little confused; what did you upgrade from? OpenAFS 1.6.5 is not
in squeeze (even in backports). Do you just mean that you upgraded the
kernel from 2.6.32 to 3.2, but the machine in general was running
wheezy? Or were you upgrading from squeeze, but somehow had OpenAFS
1.6.5 on it?

Can you check 'rxdebug <client> 7001 -version' and make sure that the
version number and 'built' date make sense? It should not be possible
to be running the old kernel module or anything like that, but just as a
sanity check...

> [76628.451414] BUG: unable to handle kernel paging request at 
> 0000000000004f62
> [76628.452165] IP: [<ffffffffa037988c>] lock_page+0x13/0x2c [openafs]

What filesystem are you using for your openafs cache?

If you're using a weird filesystem for that, that might explain this,
but to try and get more information:

Could you install the linux-image-*-dbg package for your kernel, and run
'crash', and then run:

crash> dis lock_page


crash> dis afs_linux_read_cache

and provide the output? If 'crash' refuses to run, try giving it the
path to your vmlinux file (this should be included in the -dbg package

Andrew Deason