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Re: [Qemu-devel] test-filter-mirror hangs
From: |
Jason Wang |
Subject: |
Re: [Qemu-devel] test-filter-mirror hangs |
Date: |
Wed, 23 Jan 2019 10:43:11 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 |
On 2019/1/22 上午2:56, Peter Maydell wrote:
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
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?
Thanks
[1]
commit 8258292e18c39480b64eba9f3551ab772ce29b5d (HEAD, refs/bisect/bad)
Author: Peter Xu <address@hidden>
Date: Tue Oct 9 14:27:15 2018 +0800
monitor: Remove "x-oob", offer capability "oob" unconditionally
Out-of-band command execution was introduced in commit cf869d53172.
Unfortunately, we ran into a regression, and had to turn it into an
experimental option for 2.12 (commit be933ffc23).
http://lists.gnu.org/archive/html/qemu-devel/2018-03/msg06231.html
The regression has since been fixed (commit 951702f39c7 "monitor: bind
dispatch bh to iohandler context"). A thorough re-review of OOB
commands led to a few more issues, which have also been addressed.
This patch partly reverts be933ffc23 (monitor: new parameter "x-oob"),
and makes QMP monitors again offer capability "oob" whenever they can
provide it, i.e. when the monitor's character device is capable of
running in an I/O thread.
Some trivial touch-up in the test code is required to make sure
qmp-test
won't break.
Reviewed-by: Markus Armbruster <address@hidden>
Reviewed-by: Marc-André Lureau <address@hidden>
Signed-off-by: Peter Xu <address@hidden>
Message-Id: <address@hidden>
[Conflict with "monitor: check if chardev can switch gcontext for OOB"
resolved, commit message updated]
Signed-off-by: Markus Armbruster <address@hidden>
- [Qemu-devel] test-filter-mirror hangs, Peter Maydell, 2019/01/11
- Re: [Qemu-devel] test-filter-mirror hangs, Dr. David Alan Gilbert, 2019/01/11
- Re: [Qemu-devel] test-filter-mirror hangs, Zhang Chen, 2019/01/14
- Re: [Qemu-devel] test-filter-mirror hangs,
Jason Wang <=
- Re: [Qemu-devel] test-filter-mirror hangs, Dr. David Alan Gilbert, 2019/01/23
- Re: [Qemu-devel] test-filter-mirror hangs, Jason Wang, 2019/01/23
- Re: [Qemu-devel] test-filter-mirror hangs, Dr. David Alan Gilbert, 2019/01/24
- Re: [Qemu-devel] test-filter-mirror hangs, Peter Xu, 2019/01/24
- Re: [Qemu-devel] test-filter-mirror hangs, Jason Wang, 2019/01/24
- Re: [Qemu-devel] test-filter-mirror hangs, Markus Armbruster, 2019/01/25
- Re: [Qemu-devel] test-filter-mirror hangs, Jason Wang, 2019/01/24
- Re: [Qemu-devel] test-filter-mirror hangs, Markus Armbruster, 2019/01/24
- Re: [Qemu-devel] test-filter-mirror hangs, Jason Wang, 2019/01/24
- Re: [Qemu-devel] test-filter-mirror hangs, Markus Armbruster, 2019/01/25