Please cc: me on QMP issues. 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? 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? Why is ignoring errors a good idea?
