Re: Experiencing hangs on SMP box with no console messages given for clues. Details inside.

On Thu, Mar 08, 2007 at 03:40:41PM -0500, Kris Kennaway wrote:
> On Thu, Mar 08, 2007 at 06:59:27AM -0600, Tillman Hodgson wrote:
> > Howdy folks,
> > 
> > These has been happening every few days for a few weeks now. When it
> > occurs, there's no messages logged to the console or to syslog -- it
> > just silently hangs. I added the break-to-debugger option so that I can
> > at least reboot it remotely via the serial console.
> > 
> > I've been following the -current kernel fairly closely in hopes that it
> > was just due to a transitory -current problem. I don't mind rebuilding a
> > kernel with special options if it's useful -- I'll be rebuilding this
> > morning with WITNESS and INVARIANTS for sure.
> 
> Let us know when you have the corresponding debugging.

[root_at_athena /usr/src/sys/i386/conf]# diff ATHENA GENERIC
24c24
< ident         ATHENA
---
> ident         GENERIC
71,73d70
<
< ### Tillman added 26Feb07 as per http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/serialconsole-setup.html
< options               BREAK_TO_DEBUGGER

Ran a kernel from backdated src (Feb 22) on a suggestion from Paolo,
hang occurred within 24 hours (eliminating that particular commit). I
have the core saved to work with and I'm now rebuilding a March 10
kernel.

I'm trying to follow the instructions at
http://www.freebsd.org/doc/en_US.ISO8859-1/books/faq/advanced.html#KERNEL-PANIC-TROUBLESHOOTING
and in
http://www.onlamp.com/pub/a/bsd/2002/04/04/Big_Scary_Daemons.html?page=1
but I'm running into an issue even getting gdb to start:

[root_at_athena /var/crash]# which gdb
/usr/bin/gdb
[root_at_athena /var/crash]# gdb -k
gdb: unrecognized option `-k'
Use `gdb --help' for a complete list of options.

The man page doesn't list a -k option either. /usr/src/UPDATING doesn't
seem to mention any gdb changes.

I can do it without the debug kernel but my understanding is that that's
much less useful.

-T


-- 
"If you are going to fail, you might as well fail at a difficult task.
 Failure causes others to downgrade their expectations of you in the
 future. The seriousness of this problem depends on what you attempt."
    -- Avinash Dixit & Barry Nalebuff