[arch-general] Kernel code dump retrieval

[Anatol Pomozov]

Hi

On Thu, Oct 16, 2014 at 9:11 AM, Leonidas Spyropoulos
<artafinde at gmail.com> wrote:
> On 16/10/14, Anatol Pomozov wrote:
>> When you say "produce a core dumps" what exactly you see. How do you
>> know it produces the kernel dump?
>>
> I usually build the AUR package from within X. But sometimes I do it on
> another TTY. On these cases where I do it from TTY I was able to see
> partly a core dump (messages about kernel panic and then some more
> output). The problem was that it was part of it and I could not scroll
> to see the whole message.

So you don't need full kernel memory dump that preserves content of
RAM on crash. You just need kernel stack trace message, do you?

Check pause_on_oops kernel parameter
https://www.kernel.org/doc/Documentation/kernel-parameters.txt it
might help you to prevent scrolling.

Another option is to use serial port and watch kernel messages from a
remote machine https://wiki.archlinux.org/index.php/Working_with_the_serial_console



>
>>
>> After the crash happens kernel cannot write anything to disk nor send
>> via network. Dealing with disk/network/... requires valid kernel data
>> structures and you don't have them anymore.
>>
>> Once kernel crashed it has only one option - reboot.
>>
>> Check kdump https://wiki.archlinux.org/index.php/Kdump - it is
>> probably what you are looking for.
>
> But that invoves a kernel compilation (right?) and I seem to end up in the same
> problem as before -
> kernel crashing when compiling big projects.
Hm... I would recommend you to run memory test to make sure it is not
a hardware problem with your RAM.

>
> Is there a kernel with Kdump enabled already?

I do not think so. I was compiling my custom kdump kernel, but it can
be done on other machine and then be installed on the problematic
machine.