panic in deadlkres() on r267110

[Attilio Rao]

On Fri, Jun 6, 2014 at 5:06 PM, Glen Barber <gjb at freebsd.org> wrote:
> On Fri, Jun 06, 2014 at 07:23:49AM -0700, Sean Bruno wrote:
>> On Fri, 2014-06-06 at 10:12 -0400, Glen Barber wrote:
>> > Two machines in the cluster panic last night with the same backtrace.
>> > It is unclear yet exactly what was happening on the systems, but both
>> > are port building machines using ports-mgmt/tinderbox.
>> >
>> > Any ideas or information on how to further debug this would be
>> > appreciated.
>> >
>> These machines were happily running r266621 previously to this update
>> yesterday.  So, that gives us a bisection point.
>>
>
> Some more debug information.  Thank you to Attilio for information on
> what data to get.
>
> Script started on Fri Jun  6 15:00:53 2014
> command: /bin/sh
> # kgdb ./kernel.debug /var/crash/vmcore.0
> [...]
> #0  doadump (textdump=-946873840) at pcpu.h:219
> 219             __asm("movq %%gs:%1,%0" : "=r" (td)
> (kgdb) p/x allproc_lock.sx_lock
> $1 = 0xfffff813ae7f4924
> Current language:  auto; currently minimal
> (kgdb) p ((struct thread *)0xfffff813ae7f4924)

The actual thread address is: 0xfffff813ae7f4920.

Then look at the GDB threads list and match with the tid.

Attilio