Re: [Qemu-discuss] qemu hangs

[Peter Maydell]

On 16 August 2016 at 18:41, Nerijus Baliūnas
<address@hidden> wrote:
> 2016-08-16 20:26, Peter Maydell rašė:
>>>
>>> Yes, it still hangs:
>>>
>>> # gdb /usr/bin/qemu-system-alpha
>>> (gdb) r -S -no-user-config -nodefaults -nographic -M none -qmp
>>> unix:/var/lib/libvirt/qemu/capabilities.monitor.sock,server,nowait
>>> -pidfile
>>> /var/lib/libvirt/qemu/capabilities.pidfile
>>> Starting program: /usr/bin/qemu-system-alpha -S -no-user-config
>>> -nodefaults
>>> -nographic -M none -qmp
>>> unix:/var/lib/libvirt/qemu/capabilities.monitor.sock,server,nowait
>>> -pidfile
>>> /var/lib/libvirt/qemu/capabilities.pidfile
>>> [Thread debugging using libthread_db enabled]
>>> Using host libthread_db library "/lib64/libthread_db.so.1".
>>> [New Thread 0x7fffc9708700 (LWP 13010)]
>>> ^C
>>
>>
>> Has it actually hung, or is it just waiting for you to talk
>> QMP protocol to it on the socket ?
>
>
> Probably hung, because the same command launches on another PC,
> process is running and the shell returns.

Even with -daemonize not supplied? It shouldn't return
you to the shell prompt if you don't pass that option!

>> I think what is happening here is that libvirt starts these
>> QEMU processes to query them for what they support. What should
>> happen is that QEMU is started, libvirt talks QMP protocol to
>> them and then stops the QEMU processes when it's found out the
>> answers to its questions. I think we need to somehow get a
>> log of what libvirt is doing on the QMP socket to find out
>> whether this bug is in QEMU (eg libvirt asks it to do something
>> and it hangs) or in libvirt (eg libvirt doesn't tell
>> QEMU to quit).
>
>
> Yes, but as I wrote above, the command runs on another PC
> even without libvirt. So most probably something wrong with qemu.

Does the same binary work on one PC and not on the other?
(not just the same command).

thanks
-- PMM