Re: [Qemu-devel] latest rc: virtio-blk hangs forever after migration

[Andrey Korolyov]

On Tue, Jul 15, 2014 at 9:32 PM, Andrey Korolyov <address@hidden> wrote:
> On Tue, Jul 15, 2014 at 7:57 PM, Paolo Bonzini <address@hidden> wrote:
>> Il 13/07/2014 17:29, Andrey Korolyov ha scritto:
>>
>>> Small follow-up: issue have probabilistic nature, as it looks - by
>>> limited number of runs, it is reproducible within three cases:
>>>  1) live migration went well, I/O locked up,
>>>  2) live migration failed by timeout, I/O locked up,
>>>  3) live migration went well and disk was not locked, but on backward
>>> migration we are always hitting 2).
>>
>>
>> Can you provide a gdb backtrace of case (2)?
>>
>> Paolo
>>
>
> Sorry, I`ve mixed reset into. The timeout on migration happens if
> there was already hang before reset. Bt-reset and bt-noreset
> corresponds to two backtraces first of which had hang+reset
> previously. As it looks by bisection, the problem introduced by fix
> targeted to patch exactly the same behavior. Moreover, rolling
> problematic commit back (9a833121eb253589143ff8fe30be8a311a2c16b3)
> fixes situation for me.

Sorry, wrong hash given, right one is the
9b1786829aefb83f37a8f3135e3ea91c56001b56. I am referring to the
http://marc.info/?l=qemu-devel&m=140174116403095&w=2 above. Also I
forgot to mention that two backtraces are absolutely identical, so the
problem is linked to the emulator state for sure.