Re: [Qemu-devel] [PULL 10/40] migration: Delay start of migration main routines

[Juan Quintela <quintela@redhat.com>]

Kevin Wolf <kwolf@redhat.com> wrote:
> Am 18.05.2018 um 14:14 hat Kevin Wolf geschrieben:
>> Am 18.05.2018 um 12:34 hat Dr. David Alan Gilbert geschrieben:
>> > * Kevin Wolf (kwolf@redhat.com) wrote:
>> > > Am 16.05.2018 um 01:39 hat Juan Quintela geschrieben:
>> > > > We need to make sure that we have started all the multifd threads.
>> > > > 
>> > > > Signed-off-by: Juan Quintela <quintela@redhat.com>
>> > > > Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
>> > > 
>> > > This commit makes qemu-iotests 091 hang for me. Either it breaks
>> > > backward compatibility intentionally and we need to update the test
>> > > case, or there is a bug somewhere.
>> > 
>> > It's not an intentional break.
>> > And the avocado tcp and exec migrations pass OK, so hmm.
>> 
>> In case it helps, 169 fails as well and I got a core dump of an aborting
>> QEMU process:
>> 
>> (gdb) bt
>> #0  0x00007ff079f779fb in raise () at /lib64/libc.so.6
>> #1  0x00007ff079f79800 in abort () at /lib64/libc.so.6
>> #2  0x00007ff079f700da in __assert_fail_base () at /lib64/libc.so.6
>> #3  0x00007ff079f70152 in  () at /lib64/libc.so.6
>> #4  0x000055c2126f067b in bdrv_close_all () at block.c:3375
>> #5 0x000055c2123c54a6 in main (argc=<optimized out>, argv=<optimized
>> out>, envp=<optimized out>) at vl.c:4682
>> 
>> If I understand correctly, that assertion failure means that someone is
>> still holding a reference to a block device after all user-owned
>> references have been closed. I suppose this was the source qemu and
>> the migration hasn't been completed properly, though I haven't looked at
>> the code yet and this idea might be completely wrong.
>> 
>> Anyway, 091 is certainly the simpler test case to play with, but maybe
>> this gives you another hint.
>
> Any news on this? This is starting to become really annoying as a
> hanging test suite impacts my ability to properly test block layer
> patches.
>
> If there is no hope of quickly getting a proper fix for this, we may
> have to revert something for now to fight the symptoms at least.

Hi

I am looking into this.  I have been on vacation the end of last week,
and to make things nicer, body decided that taking a stomach flu before
returning was a great idea.

Coping with email/tests.

Later, Juan.