Re: [Qemu-devel] Aborts in iotest 169

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Luiz Capitulino (lcapitulino@redhat.com) wrote:
> On Wed, 23 Jan 2019 17:12:35 +0100
> Max Reitz <mreitz@redhat.com> wrote:
> 
> > On 23.01.19 17:04, Luiz Capitulino wrote:
> > > On Wed, 23 Jan 2019 16:48:49 +0100
> > > Max Reitz <mreitz@redhat.com> wrote:
> > >   
> > >> Hi,
> > >>
> > >> When running 169 in parallel (e.g. like so:
> > >>
> > >> $ while TEST_DIR=/tmp/t0 ./check -T -qcow2 169; do; done
> > >> $ while TEST_DIR=/tmp/t1 ./check -T -qcow2 169; do; done
> > >> $ while TEST_DIR=/tmp/t2 ./check -T -qcow2 169; do; done
> > >> $ while TEST_DIR=/tmp/t3 ./check -T -qcow2 169; do; done
> > >>
> > >> in four different shells), I get aborts:  
> > > 
> > > OK, is this part of a test-suite that's also running migration
> > > tests in parallel or in sequence? In other words, what does
> > > iotests have to do with migration (sorry if this is stupid
> > > question, but it's been years I don't do qemu).  
> > 
> > They run migration tests in sequence, but if you run multiple test
> > instances in parallel, well, then they will be run in parallel.
> > 
> > The only reason I CC'd you was because you were so prominent in git
> > blame. O:-)
> 
> Yeah, that's often the case with me :-)
> 
> > > When this happened in the past it meant some QEMU code skipped a
> > > transition, but I can't tell what this has to do with iotests.  
> > 
> > Well, this iotest (which tests a migration configuration) sometimes
> > apparently results in this invalid transition.  But that can't be just
> > the test's fault, as qemu should handle that gracefully.
> 
> Does iotest run a guest or does it only executes parts of qemu
> code? If it's the latter, then I'd guess the test code is missing
> calling qemu code that sets the appropriate state between
> running and postmigrate states.
> 
> > It's probably an issue in the migration code and not so much in vl.c, yes...
> 
> Yeah, I'll let the migration people jump in.

Can we get a log of the qmp commands when it fails?
A 'running->postmigrate' transition is a bit weird; you could get a
something->postmigrate if you migrate a VM twice, and the source is
already in postmigrate, so it tells the destination to go into
postmigrate.   That's odd in itself, but not *that* odd.
But then why is it going running->postmigrate?  That suggests
the source is currently running when it receives an incoming migration,
and that really shouldn't happen.

Dave
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK