Re: [Qemu-devel] Supplying QCOW2 as 'file' driver to `blockdev-add` results in a QEMU crash

[Eric Blake <eblake@redhat.com>]

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On 06/15/2016 09:38 AM, Eric Blake wrote:
> On 06/15/2016 09:17 AM, Max Reitz wrote:
>> On 15.06.2016 11:58, Kashyap Chamarthy wrote:
>>> Seems like supplying "qcow2" file BlockdevDriver option to QMP
>>> `blockdev-add` results in a SIGSEGV:
>>>
>>> 	[...]
>>>     Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
>>>     0x0000555555a0121f in visit_type_BlockdevRef ()
>>> 	[...]
>>>
>>> Reproducer
>>> ----------
>>
>> Even simpler reproducer:
>>
>> {'execute':'blockdev-add','arguments':{'options':{'driver':'raw'}}}
>>
>> Seems like a QAPI problem to me, and bisecting yields
>> dbf11922622685934bfb41e7cf2be9bd4a0405c0 as the culprit.
> 
> I'm looking into it. Thanks for the testcase.

Okay, the problem is based on error handling - you have a missing 'file'
argument.  That patch consolidated things to do two things at once
instead of two calls where the second was skipped if the first failed;
and now ends up dereferencing NULL.  I didn't notice or test it at the
time, so I get to enhance the testsuite as part of my patch.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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