panic: witness_warn head/amd64 @r285741 on 1 of 2 machines

[David Wolfskill]

On Tue, Jul 21, 2015 at 10:28:32PM +0300, Konstantin Belousov wrote:
> ...
> Indeed, thank you.
> ithread_loop() at ithread_loop+0xa6/frame 0xfffffe083b9c0a70
> fork_exit() at fork_exit+0x84/frame 0xfffffe083b9c0ab0
> fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe083b9c0ab0
> --- trap 0, rip = 0, rsp = 0xfffffe083b9c0b70, rbp = 0 ---
> suspending ithread with the following locks held:
> shared rw udpinp (udpinp) r = 3 (0xfffff80010c7d7b0) locked @ /usr/src/sys/netinet6/in6_pcb.c:1174
> panic: witness_warn
> cpuid = 3
> 
> So it looks like net swi, leaking some udp6 lock.

Curiouser and curiouser...  While I'm not taking any special pains to
avoid building IPv6, I'm not actively actually doing anything with it
(IPv6), either (for both the failing machine and my laptop).

Once I'm back home, I should be able to poke around in ddb after
re-creating the panic, if that would be a useful thing for me to do (and
given some hints as to what to poke).

Naturally, I'm also happy to change bits of sources, rebuild, and
smoke-test.

A quick check from the SVN update output only shows r285710, r285711, and
r285740 in the range from (r285685,r285741] -- as the kernel running
r285685 had no known issues -- that touched sys/netinet6/*.

Peace,
david
-- 
David H. Wolfskill				david at catwhisker.org
Those who murder in the name of God or prophet are blasphemous cowards.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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