Re: [Qemu-devel] kvm segfaulting

[Stefan Priebe - Profihost AG]

Hi,

> Some trace that a request was actually cancelled, but I think I
> believe
Ah but that must be in guest not on host right? How to grab that from
client when it is crashing?

> that.  This seems to be the same issue as commits
> 1bd075f29ea6d11853475c7c42734595720c3ac6 (iSCSI) and
> 473c7f0255920bcaf37411990a3725898772817f (rbd), where the "cancelled"
> callback is called before the "complete" callback.
If there is the same code in virtio-scsi it might be.

> Note how virtio_scsi_request_cancelled is protected against
> r->hba_private == NULL, while virtio_scsi_command_complete doesn't.
> That's by design, because the latter should never happen or you could
> get data corruption in the guest.
No idea ;-) i'm not even a C programmer at all.

> What version are you running?  Does the rbd backend have the above
> commit?
librbd 0.56.2
qemu current master git (10442558ab1797bfbb01285b909e34c5cf038f12)

Stefan
Am 11.02.2013 15:12, schrieb Paolo Bonzini:
> Il 11/02/2013 15:02, Stefan Priebe - Profihost AG ha scritto:
>> Hi,
>>
>> nothing. What are you searching for?
> 
> Some trace that a request was actually cancelled, but I think I believe
> that.  This seems to be the same issue as commits
> 1bd075f29ea6d11853475c7c42734595720c3ac6 (iSCSI) and
> 473c7f0255920bcaf37411990a3725898772817f (rbd), where the "cancelled"
> callback is called before the "complete" callback.
> 
> Note how virtio_scsi_request_cancelled is protected against
> r->hba_private == NULL, while virtio_scsi_command_complete doesn't.
> That's by design, because the latter should never happen or you could
> get data corruption in the guest.
> 
> What version are you running?  Does the rbd backend have the above commit?
> 
> Paolo
> 
>> Stefan
>> Am 11.02.2013 14:59, schrieb Paolo Bonzini:
>>> Il 11/02/2013 14:58, Stefan Priebe - Profihost AG ha scritto:
>>>> Hi Paolo,
>>>>
>>>> as the guest crashes i can't check the guest. On the host i just have
>>>> the segmentation fault line. Anything else is from the bootprocess or
>>>> enabling the tap device. So nothing suspicious.
>>>
>>> What about log from the serial console?
>>>
>>> Paolo
>>>
>>>> Greets,
>>>> Stefan
>>>>
>>>> Am 11.02.2013 14:56, schrieb Paolo Bonzini:
>>>>>> Il 11/02/2013 14:35, Stefan Priebe - Profihost AG ha scritto:
>>>>>>>> Hi Stefan,
>>>>>>>>
>>>>>>>> yes i use virtio-scsi-pci in all my guests. As it is the only one where
>>>>>>>> i can use fstrim from guest to storage with rbd ;-)
>>>>>>
>>>>>> Can you check for anything suspicious in the kernel console output?
>>>>>>
>>>
>