Subject: Re: Getting a kernel panic dump back (or not)
To: Robert Swindells <>
From: Richard Earnshaw <>
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.