extract panic message & debugging from vmcore.0 ?

[Michael W. Lucas]

On Thu, Jun 29, 2017 at 07:35:02PM -0700, Mark Millard wrote:
> Look for /usr/libexec/kgdb .
> 
> But for some, most, or all TARGET_ARCH's the
> FreeBSD folks now recommend using kgdb from
> ports. (Which you built and installed.)
> 
> /usr/libexec/kgdb is more for means-of-last-resort
> use when one can not get to the point of having
> the port kgdb around.


Thanks for the info! Seriously.

...

> > Well, that's not good. I did more searching and found
> > /usr/src/tools/debugscripts/README.
> > 
> > # cd /usr/obj/usr/src/sys/GENERIC
> > # make gdbinit
> > # gdb kernel.debug
> 
> Did you miss a /var/crash/vmcore.0 above?

Same error with and without /var/crash/vmcore.0

Looks what I really need is crashinfo(8). Which isn't
referenced... anywhere, far as I can tell. (That's ok, someone will
read the book and update the Handbook. ;-)

> Separately. . .
> 
> I'm no expert but you might need to pick
> between the default minidump vs. a full
> memory dump depending on purposes and what
> information is to be extracted:
> 
> debug.minidump: 1
> vs.
> debug.minidump: 0
> 
> in the sysctl debug.minidump output. I
> doubt that they are fully equivalent.
> 
> Of course a full memory dump implies
> needing space ready to hold that full
> copy.

Again, thanks for that info!

==ml

-- 
Michael W. Lucas    Twitter @mwlauthor 
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