Re: Dtrace: hotkernel+buildworld -> crash

On 22 Oct, 2008, at 24:41 , Artem Belevich wrote:

> Hi,
>
> I'm not sure if it's a known issue or not, but running hotkernel
> script from DTraceToolkit-0.99
> during "make buildworld -j8" easily crashes -current  (cvsup'ed on Oct
> 20th) on amd64 (Quad core Q9450)
> when I press ^C to stop the script.
>
> Kernel is GENERIC with WITNESS/INVARIANTS disabled and some
> SCSI/wireless/NIC drivers removed.
>
> I was unable to dump kernel core - debugger always gets another trap
> and returns
> to the prompt. The box does not have serial ports, so I've typed in
> portions of stack
> traces below from the screen.
>
> One common thing across all crashes I've seen so far is that crashed
> process always
> dies in the same place with the following backtrace. Apparently it  
> attempts to
> dereference $rip which is 0.
>
> cyclic_disable_xcall+0x7
> smp_rendezvous_action
> Xrendezvous
> ----interrupt
>
> Dtrace process itself always has the same stack trace:
>
> smp_tlb_shootdown
> pmap_invalidate_page
> pmap_remove_pte
> pmap_remove
> vm_map_delete
> vm_map_remove
> uma_large_free
> free
> dtrace_buffer_free
> dtrace_state_destroy
> dtrace_close
> ...
>
> I'll try to reproduce the issue with WITNESS/INVARIANTS turned ON.  
> Perhaps that
> would provide more hints on what's wrong. Meanwhile, if someone can  
> suggest
> anything I can do to help troubleshoot this, that would be great as
> I'm a bit out of
> my depth here.
>
> -- 
> --Artem
>


Yesterday I was able to crash a machine several times with hotkernel.  
This was shile the machine
was under heavy network load. While it was idle hotkernel seems to run  
normal, but when it's loaded
as soon as I press Ctrl-C it crashes.
The machine runs latest -STABLE, but I guess the Dtrace code is the  
same in both current and stable?


--
Regards,
Nikolay Denev