Re: [Qemu-discuss] [Qemu-devel] KVM guest gets aborted if blockcommit is called

[Christian Rößner]

> Am 26.08.2015 um 15:25 schrieb Jeff Cody <address@hidden>:
> 
> On Wed, Aug 26, 2015 at 10:08:26AM +0200, Christian Rößner wrote:
>> 
>>> Am 25.08.2015 um 08:02 schrieb Christian Rößner <address@hidden>:
>>> 
>>> Hello,
>>> 
>>> I wrote this mail to the qemu-discuss mailing list, but today I am unsure, 
>>> if I chose the right list. So I copy and paste this mail here in hope 
>>> someone can respond :-)
>>> 
>>> I have reproducable problems with some code in qemu-coroutine.c:
>>> 
>>> 
>>> void qemu_coroutine_enter(Coroutine *co, void *opaque)
>>> {
>>>   Coroutine *self = qemu_coroutine_self();
>>>   CoroutineAction ret;
>>> 
>>>   trace_qemu_coroutine_enter(self, co, opaque);
>>> 
>>>   if (co->caller) {
>>>       fprintf(stderr, "Co-routine re-entered recursively\n");
>>>       abort();   <————————— This one triggers 4 or 5 out of ten tests to 
>>> use the blockcommit feature
>>>   }
>> 
>> Caught Co-routine SIGABRT while a blockcommit operation was running.
>> 
>> Recompiled with debugging symbols and I connected gdb to the process:
>> 
>> (gdb) bt
>> #0  0x00007f4b6e6ccb8e in raise () from /lib64/libc.so.6
>> #1  0x00007f4b6e6ce391 in abort () from /lib64/libc.so.6
>> #2  0x0000555a316a8c39 in qemu_coroutine_enter (co=0x555a34651a50, 
>> opaque=0x0)
>>    at 
>> /var/tmp/portage/app-emulation/qemu-2.4.0/work/qemu-2.4.0/qemu-coroutine.c:111
>> #3  0x0000555a316a8eda in qemu_co_queue_run_restart (address@hidden)
>>    at 
>> /var/tmp/portage/app-emulation/qemu-2.4.0/work/qemu-2.4.0/qemu-coroutine-lock.c:59
>> #4  0x0000555a316a8b53 in qemu_coroutine_enter (co=0x555a33d271b0, 
>> opaque=<optimized out>)
>>    at 
>> /var/tmp/portage/app-emulation/qemu-2.4.0/work/qemu-2.4.0/qemu-coroutine.c:118
>> #5  0x0000555a316e3adf in bdrv_co_aio_rw_vector (address@hidden,
>>    address@hidden, address@hidden,
>>    address@hidden, address@hidden(unknown: 0),
>>    address@hidden <mirror_read_complete>, opaque=0x555a3367d2c0, 
>> address@hidden)
>>    at 
>> /var/tmp/portage/app-emulation/qemu-2.4.0/work/qemu-2.4.0/block/io.c:2142
>> #6  0x0000555a316e4b1e in bdrv_aio_readv (address@hidden,
>>    address@hidden, address@hidden,
>>    address@hidden, address@hidden <mirror_read_complete>,
>>    address@hidden)
>>    at 
>> /var/tmp/portage/app-emulation/qemu-2.4.0/work/qemu-2.4.0/block/io.c:1744
>> #7  0x0000555a316e2ccf in mirror_iteration (s=0x555a34a0c250)
>>    at 
>> /var/tmp/portage/app-emulation/qemu-2.4.0/work/qemu-2.4.0/block/mirror.c:302
>> #8  mirror_run (opaque=0x555a34a0c250)
>>    at 
>> /var/tmp/portage/app-emulation/qemu-2.4.0/work/qemu-2.4.0/block/mirror.c:512
>> #9  0x0000555a316a9a5a in coroutine_trampoline (i0=<optimized out>, 
>> i1=<optimized out>)
>>    at 
>> /var/tmp/portage/app-emulation/qemu-2.4.0/work/qemu-2.4.0/coroutine-ucontext.c:80
>> #10 0x00007f4b6e6df4a0 in ?? () from /lib64/libc.so.6
>> #11 0x00007ffe67b71840 in ?? ()
>> #12 0x0000000000000000 in ?? ()
>> (gdb)
>> 
>> Please, could someone reply to me :-)
>> 
>> Thanks
>> 
>> Christian
> 
> Hi Christian,
> 
> I think  you may be running into a bug that is fixed by a recent patch
> (after v2.4.0): 
> 
> commit e424aff5f307227b1c2512bbb8ece891bb895cef
> Author: Kevin Wolf <address@hidden>
> Date:   Thu Aug 13 10:41:50 2015 +0200
> 
>    mirror: Fix coroutine reentrance
> 
> 
> Could you retry with qemu.git/master, and see if that fixes the issue
> you are seeing?

Until now, everything looks perfectly. No issues. Backup is running smoothly.

Thanks very much. If nothing changes until tonight, I am going to close the bug 
report.

Christian

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