Re: unkillable dpkg-query processes

[Bernd Zeimetz <bernd@bzed.de>]

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> Ok, the key in the trace is:
> 
> Nov  2 16:25:30 titan kernel: [  978.134874]   CPU[  1]: TSTATE[0000000080009603] TPC[000000000067d2e0] TNPC[000000000067d2d4] TASK[aptitude:3204]
> Nov  2 16:25:30 titan kernel: [  978.257809]              TPC[_write_unlock_irq+0x20/0x110]
>  ...
> Nov  2 16:25:30 titan kernel: [  978.507778]   CPU[  3]: TSTATE[0000000011009605] TPC[00000000004419f8] TNPC[00000000004419fc] TASK[aptitude:3203]
> Nov  2 16:25:30 titan kernel: [  978.630707]              TPC[cheetah_xcall_deliver+0x174/0x23c]
> 
> The first symbol is misleading, it says _write_unlock_irq but actually
> in the assembler the PC is in the spinlock read spinning loop
> section.  So actually it's hanging in _spin_lock().
> 
> CPU #3 is trying to send a cross-call message interrupt, but for
> some reason that isn't making forward progress.
> 
> Let's see what's calling these things by adding some more debugging
> information.  Please retry the test with the following patch on
> top of the original sysrq-g debugging patch and please get new
> logs when it hangs.


Today I was a bit out of luck, either the machine crashed so badly that
it just didn't react on anything anymore, or it didn't crash.
The machine went amok a bit slower when I did the following things,
which also resulted in the attached sysrq output.
- run stress -c 2 to get the load up, didn't need that the last time...
- run something like `while true; do echo g > /proc/sysrg-trigger; sleep
0.5; done`
- run aptitude -u several times until the machine died.

So I'm not sure if the result is really useful for you - if not just let
me know. I've attached the last ~10-20 sysrq-g outputs - as it was
running in a loop I have a ton of them. In case you're wondering: http
is aptitude's http method.

We'll also run the patched Kernel on a US II machine form tomorrow on -
but it always took a longer time until it crashed, so we'll see if it
happens at all.

Thanks for your work,


Bernd


-- 
Bernd Zeimetz
<bernd@bzed.de>                         <http://bzed.de/>

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