Panic on boot. How do I get a kernel dump.

Tom Cumming tcumming123 at
Mon Apr 23 22:19:54 UTC 2007

On 4/23/07, Ivan Voras <ivoras at> wrote:
> Tom Cumming wrote:
> > All of the doc's I can find are for getting a kernel dump after it's
> booted
> > (i.e., set the dumpdev using dumpon, etc.). I have a panic during boot
> and
> > it says it won't dump b/c there's no dump device. I cannot find any
> doc's
> > anywhere that mention how to set the dump device before you boot (i.e.,
> > from
> > the loader, patch the kernel, whatever...). Does anyone know how to get
> an
> > early dump?
> Can you boot from a Live CD ("Fixit CD", CD1 in the set), and either
> configure it from there, or build a kernel with debugging installed so
> it presents you the debugger when it panics?

   I'm getting into the debugger when it panics (I started using 7-current).
I'd rather get a dump because then I have a snapshot of the kernel when it
panics and I can do a postmortem at my leisure.

   It also got me curious.. I'm sure there's got to be a way to do it!

Thanx, tom

More information about the freebsd-current mailing list