obtaining a kernel crash dump

Peter Pentchev roam at ringlet.net
Wed May 19 07:20:27 PDT 2004

On Wed, May 19, 2004 at 04:34:42PM +0300, Nick Strebkov wrote:
> Hi there.
> I can't obtain a crash dump.
> % cat /sys/i386/conf/DEVEL | grep makeoptions
> makeoptions     DEBUG=-g
> % cat /etc/rc.conf| grep dump
> dumpdev="/dev/ar0s1b"
> dumpdir="/var/crash"
> I'm testing my kernel patch and the following is what I see in
> /var/log/messages:

Can you force the kernel to dump by using DDB?  Place 'options DDB' in
your kernel config, then, when the system is quiescent, hit Ctrl-Alt-Esc
and type 'panic' at the DDB prompt.

If this works, and you get a crash dump, then the problem might be that
with your kernel patch, the kernel is panicking in a low-level layer,
like memory management or disk drivers or something like that, and it
simply cannot make a crash dump, since that would mean invoking code
that depends on bad data or something.


Peter Pentchev	roam at ringlet.net    roam at sbnd.net    roam at FreeBSD.org
PGP key:	http://people.FreeBSD.org/~roam/roam.key.asc
Key fingerprint	FDBA FD79 C26F 3C51 C95E  DF9E ED18 B68D 1619 4553
Hey, out there - is it *you* reading me, or is it someone else?
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