Subject: Re: Getting a kernel panic dump back (or not)
To: Robert Swindells <rjs@fdy2.demon.co.uk>
From: Richard Earnshaw <rearnsha@arm.com>
List: port-arm
Date: 01/09/2004 15:46:54
>
> Richard Earnshaw wrote:
> >Hmm, so I've just hand my shark panic again with the same panic as point 2
> >in pr port-arm/23581 :-(
>
> >This time, however, on typing sync at the ddb prompt it paniced again (not
> >too unusual). However, on typing reboot it then managed to do a full dump
> >(or at least, it went through the motions of doing so).
>
> >So I was somewhat disappointed to find that on reboot, savecore announced
> >that there was nothing to be found :-(
>
> >Anyway, I've DD'ed my entire swap partition (there may be something
> >there). Does anyone have any ideas on how to extract the kernel dump from
> >it? Better still, does anyone know how to make savecore do its job
> >properly?
>
> The code to dump the core in arm/vm_machdep_arm.c looks identical to the
> i386 version. I have used savecore fairly recently on i386.
>
In fact, I think I've found the problem (or one of them). At no time does
the ARM dump code set KCORE_MAGIC in the dump, so savecore will never
recognize it :-(
There's other problems, such as regularly locking up while trying to dump
as well, but even if it succeeds, it's never going to be recognized as
things stand.
R.