Re: [Qemu-devel] [PATCH 0/6] virtio: refactor host notifiers

[tu bo <tubo@linux.vnet.ibm.com>]

Hi Christian:

I got the same crash with qemu master + assertion patch + "[PATCH 0/6] 
virtio: refactor host notifiers" +  Paolo's fix,

(gdb) bt
#0  blk_aio_read_entry (opaque=0x0) at block/block-backend.c:916
#1  0x000002aa2e8e88fe in coroutine_trampoline (i0=<optimized out>, 
i1=-1677703696) at util/coroutine-ucontext.c:78
#2  0x000003ffa85d150a in __makecontext_ret () from /lib64/libc.so.6


On 03/30/2016 12:27 AM, Christian Borntraeger wrote:
> On 03/29/2016 03:50 PM, Paolo Bonzini wrote:
>>
>>
>> On 29/03/2016 13:45, Cornelia Huck wrote:
>>>>> Hi Tu Bo,
>>>>>
>>>>> please always include the assertion patch at
>>>>> https://lists.gnu.org/archive/html/qemu-block/2016-03/msg00546.html in
>>>>> your tests.  Can you include the backtrace from all threads with that patch?
>>>>>
>>>> thanks for your reminder about the assertion patch. Here is the
>>>> backtrace with qemu master + assertion patch + "[PATCH 0/6] virtio:
>>>> refactor host notifiers",
>>>
>>> FWIW, I've been running this in a reboot loop for the last 2 1/2 hours.
>>> Could you perhaps share your command line?
>>
>>  From code inspection, the following is also necessary or at least a
>> good idea:
>>
>> diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
>> index 6fb29e3..7fa8477 100644
>> --- a/hw/block/dataplane/virtio-blk.c
>> +++ b/hw/block/dataplane/virtio-blk.c
>> @@ -258,7 +258,7 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
>>       aio_context_acquire(s->ctx);
>>
>>       /* Stop notifications for new requests from guest */
>> -    virtio_queue_aio_set_host_notifier_handler(s->vq, s->ctx, false, false);
>> +    virtio_queue_aio_set_host_notifier_handler(s->vq, s->ctx, true, false);
>>
>>       /* Drain and switch bs back to the QEMU main loop */
>>       blk_set_aio_context(s->conf->conf.blk, qemu_get_aio_context());
>>
>
> Right. Tu Bo, you seem to have the best testcase for this.
> Does your setup runs fine with this on top?
>
> CHristian
>