Re: [Qemu-devel] test-filter-mirror hangs

[Peter Maydell]

On Thu, 17 Jan 2019 at 09:46, Jason Wang <address@hidden> wrote:
>
>
> On 2019/1/15 上午12:33, Zhang Chen wrote:
> >
> >
> > On Sat, Jan 12, 2019 at 12:15 AM Dr. David Alan Gilbert
> > <address@hidden <mailto:address@hidden>> wrote:
> >
> >     * Peter Maydell (address@hidden
> >     <mailto:address@hidden>) wrote:
> >     > Recently I've noticed that test-filter-mirror has been hanging
> >     > intermittently, typically when run on some other TCG architecture.
> >     > In the instance I've just looked at, this was with s390x guest on
> >     > x86-64 host, though I've also seen it on other host archs and
> >     > perhaps with other guests.
> >
> >     Watch out to see if you really do see it for other guests;
> >     it carefully avoids using virtio-net to avoid vhost; but on s390x it
> >     uses virtio-net-ccw - could that hit the vhost it was trying to avoid?
> >
> >     > Below is a backtrace, though it seems to be pretty unhelpful.
> >     > Anybody got any theories ? Does the mirror test rely on dirty
> >     > memory bitmaps like the migration test (which also hangs
> >     > occasionally with TCG due to some bug I'm sure we've investigated
> >     > in the past) ?
> >
> >     I don't think it relies on the CPU at all.

> >  I have no idea about this currently, but Jason and I designed the
> > test case.
> > Add Jason: Have any comments about this ?
>
>
> I can't reproduce this locally with s390x-softmmu. It looks to me the
> test should be independent to any kinds of emulation. It should pass
> when mainloop work.

I've just seen a hang with ppc64 guest on s390x host, so it is
indeed not specific to s390x guest (and so not specific to
virtio-net either, since the ppc64 guest setup uses e1000).

thanks
-- PMM