hangup (livelock) - db> prompt in endless loop

[Anton Yuzhaninov]

Anton Yuzhaninov wrote:
> My box with fresh current sometimes stops to respond.
> 
> On screen in endless loop printed debugger prompt
> 
> db>
> 
> but I can't type anything here.
> 
> Alt+Ctrl+Esc and Alt+Ctrl+Del don't stops this loop.
> 
> How I can debug this problem?
> 
> system: current from Mon Dec 15 16:16:23 MSK 2008 with GENERIC kernel, 
> amd64, SMP.
> 

with this sysctls set:

debug.debugger_on_panic=0
debug.trace_on_panic=1

db> prmopt not shown, and I can see the panic backtrace:

http://img-fotki.yandex.ru/get/3002/bgp4.1/0_25e8a_45ba0879_orig

But coredump on disk don't written.

-- 
  Anton Yuzhaninov

P. S. printing db> prompt in endless loop seems to be separate bug...