Re: [Qemu-devel] qemu process stuck in Rl state

[Stefan Hajnoczi <stefanha@gmail.com>]

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On Thu, Sep 18, 2014 at 03:21:08PM +0400, Andrey Korolyov wrote:
> On Thu, Sep 18, 2014 at 2:49 PM, Stefan Hajnoczi <stefanha@gmail.com> wrote:
> > On Wed, Sep 17, 2014 at 11:56:57PM +0400, Andrey Korolyov wrote:
> >> I`ve faced an issue with qemu VMs with very large uptime spans - half
> >> of year or so. They are hanging in running state forever and are not
> >> killable in any imaginable fashion. Tried to freeze it via freezer cg
> >> without any luck. VM itself went unresponsive with zero cpu
> >> consumption after reaching 'forever running' point.
> >>
> >> I am going to reset the host in a couple of hours, so any timed ideas
> >> for debugging this state will be very appreciated.
> >
> > A couple of shots at figuring out what the process is doing:
> >
> > cat /proc/$PID/stack
> > cat /proc/$PID/syscall
> > gdb $PID
> > (gdb) thread apply all bt
> 
> Thanks Stefan,
> 
> of course any attempts to attach to the process or dump core failed at
> very beginning. I compared proc contents with live VM and found
> nothing suspicious. The question is about what I should try to do
> facing supposedly kernel bug, if no possibility to determine which
> code is currently executing by emulator is available. Also if it may
> help, both affected VMs on different hosts has a simular process
> uptime (from end of May). Just to repeat - the process is not reacting
> to any signal, have zero CPU consumption immediately after bug
> appearance and therefore cannot be stopped/frozen.

What did cat /proc/$PID/stack and cat /proc/$PID/syscall output?

Stefan

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