Re: trying to debug xen4 & qemu-dm, Xen reports "core dump failed"

[Keir Fraser <keir.fraser@eu.citrix.com>]

On 26/01/2010 22:12, "0bo0" <0.bugs.only.0@gmail.com> wrote:

> On Tue, Jan 26, 2010 at 1:38 PM, Keir Fraser <keir.fraser@eu.citrix.com>
> wrote:
>> As root:
>>    echo '/var/core/core.%e.%u.%p' > /proc/sys/kernel/core_pattern
>> 
>> Now try starting your guest. It fails, and hopefully you have a core file in
>> /var/core/. You can load it into gdb as 'gdb /usr/lib/xen/qemu-dm
>> /var/core/name-of-core-file' and then execute bt command at the gdb prompt.
>> That hopefully tells us where qemu-dm crashed.
> 
> bash
> ulimit -c unlimited

Actually that probably only enable core dumps for the shell you are running.
Qemu-dm will inherit its ulimits from xend. So you need to enable core dumps
by running 'ulimit -c unlimited' before you start xend, or put it in the
startup script that starts xend. You could also script the echo to
/proc/sys/kernel/core_pattern, but it's definitely safe to do that later
from a shall, as it's a global value, rather than per-process.

 -- Keir