On 2019/1/24 下午5:47, Markus Armbruster wrote:
Please cc: me on QMP issues.
Ok.
Jason Wang <jasow...@redhat.com> writes:
On 2019/1/24 上午3:53, Dr. David Alan Gilbert wrote:
* Jason Wang (jasow...@redhat.com) wrote:
On 2019/1/22 上午2:56, Peter Maydell wrote:
On Thu, 17 Jan 2019 at 09:46, Jason Wang<jasow...@redhat.com> 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
<dgilb...@redhat.com <mailto:dgilb...@redhat.com>> wrote:
* Peter Maydell (peter.mayd...@linaro.org
<mailto:peter.mayd...@linaro.org>) 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
Finally reproduced locally after hundreds (sometimes thousands) times of
running.
Bisection points to OOB monitor[1].
It looks to me after OOB is used unconditionally we lose a barrier to make
sure socket is connected before sending packets in test-filter-mirror.c. Is
there any other similar and simple thing that we could do to kick the
mainloop?
Do you mean the:
/* send a qmp command to guarantee that 'connected' is setting to true. */
qmp_discard_response(qts, "{ 'execute' : 'query-status'}");
Yes.
why was that ever sufficient to know the socket was ready?
It was suggested by Fam, I don't remember the details. Can we make
sure all pending events has been processed (UNIX socket was set to
connected) after query-status is returned with an non OOB monitor?
I'm afraid I lack context. Which socket are you talking about? The
test has at least the QMP socket, the send_sock[], and recv_sock. What
exactly are you trying to accomplish?
I mean recv_sock. If mirror tries to send a packet to it before its
is_connected is set to true, packet will be dropped.
By the way, mkstemp(sock_path) followed by unix_connect(sock_path, NULL)
looks rather fishy. Why create a temporary file only to create a Unix
domain socket right over it?
I vaguely remember passing fd created by unix domain socket doesn't work
when the test is introduced. So my understanding is the author needs a
way to create a unique file name which will be used b Unix domain socket
at that time.
Why is ignoring errors a good idea?
I don't get, which error is missed, it checks the return value of both
mkstemp() and unix_connect().
Thanks
