Cannot obtain kernel dump in /var/crash

[Jeremy Chadwick]

On Thu, Feb 22, 2007 at 01:56:44PM +0200, Alexander Shikoff wrote:
> Hello,
> 
> I've discovered reproducable kernel panic but I cannot obtain a dump.
> 
> I have in rc.conf:
> 
> dumpdev="/dev/ad2s1b"
> savecore_flags="-f"
> 
> ... and in kernel configuration:
> 
> options         KDB
> options         DDB
> options         KDB_UNATTENDED
> makeoptions     DEBUG=-g                # Build kernel with gdb(1) debug symbols
> 
> My RAM size is 768 MB and swap size is 1024 MB.
> 
> When rebooting after a crash I see in console:
> Feb 22 13:40:41 crete savecore: unable to force dump - bad magic
> Feb 22 13:40:41 crete savecore: no dumps found
> 
> Any suggestions? Thanks.

Is /dev/ad2s1b the correct location?  Possibly you meant ad0s1b
or some other adX device?  (Common mistake.)

Do you have a swap device defined, particularly in /etc/fstab?o
What does swapinfo say?

Does the same happen if you say dumpdev="auto" or if you remove
the -f flag from savecore_flags?

It may be worth peeking through /etc/rc.d/dumpon and imitating
some of the commands there to see if you can reproduce it.

-- 
| Jeremy Chadwick                                 jdc at parodius.com |
| Parodius Networking                        http://www.parodius.com/ |
| UNIX Systems Administrator                   Mountain View, CA, USA |
| Making life hard for others since 1977.               PGP: 4BD6C0CB |