Re: [PATCH] qmp: Reset mon->commands on CHR_EVENT_CLOSED

[Jason Andryuk <jandryuk@gmail.com>]

On Wed, Nov 6, 2019 at 8:08 PM <no-reply@patchew.org> wrote:
>
> Patchew URL: https://patchew.org/QEMU/20191106130309.6737-1-jandryuk@gmail.com/
>
>
>
> Hi,
>
> This series failed the docker-quick@centos7 build test. Please find the testing commands and
> their output below. If you have Docker installed, you can probably reproduce it
> locally.
>
> === TEST SCRIPT BEGIN ===
> #!/bin/bash
> make docker-image-centos7 V=1 NETWORK=1
> time make docker-test-quick@centos7 SHOW_ENV=1 J=14 NETWORK=1
> === TEST SCRIPT END ===
>
>   TEST    iotest-qcow2: 268
> Failures: 060 071 176 184
> Failed 4 of 108 iotests
> make: *** [check-tests/check-block.sh] Error 1
> Traceback (most recent call last):
>   File "./tests/docker/docker.py", line 662, in <module>
>     sys.exit(main())
> ---
>     raise CalledProcessError(retcode, cmd)
> subprocess.CalledProcessError: Command '['sudo', '-n', 'docker', 'run', '--label', 'com.qemu.instance.uuid=cb707bce0c3c456d8ecec70aeb08fddc', '-u', '1003', '--security-opt', 'seccomp=unconfined', '--rm', '-e', 'TARGET_LIST=', '-e', 'EXTRA_CONFIGURE_OPTS=', '-e', 'V=', '-e', 'J=14', '-e', 'DEBUG=', '-e', 'SHOW_ENV=1', '-e', 'CCACHE_DIR=/var/tmp/ccache', '-v', '/home/patchew2/.cache/qemu-docker-ccache:/var/tmp/ccache:z', '-v', '/var/tmp/patchew-tester-tmp-mxl5_jec/src/docker-src.2019-11-06-19.55.47.20736:/var/tmp/qemu:z,ro', 'qemu:centos7', '/var/tmp/qemu/run', 'test-quick']' returned non-zero exit status 2.
> filter=--filter=label=com.qemu.instance.uuid=cb707bce0c3c456d8ecec70aeb08fddc
> make[1]: *** [docker-run] Error 1
> make[1]: Leaving directory `/var/tmp/patchew-tester-tmp-mxl5_jec/src'
> make: *** [docker-run-test-quick@centos7] Error 2
>
> real    13m1.810s
> user    0m8.371s
>
>
> The full log is available at
> http://patchew.org/logs/20191106130309.6737-1-jandryuk@gmail.com/testing.docker-quick@centos7/?type=message.
> ---
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The full logs shows iotest failures:

Failures: 060 071 176 184
Failed 4 of 108 iotests

The failures are the lack of SHUTDOWN events:
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP},
"event": "SHUTDOWN", "data": {"guest": false, "reason":
"host-qmp-quit"}}

The results are inconsistent though.  On my workstation, for one run I
had test 071 fail, but the others pass.  On another couple of runs,
they all passed.  An a final one, 176 failed.

Looking at 071, they all send a qmp command to exit, but only some of
the tests have an expected shutdown event.  Looking more broadly, it
seems like tests expect shutdown events.

I don't know the code flow, but is it possible on shutdown for the
chardev to be marked closed before the QMP event is generated?  After
this patch, those would not be sent.  If "quit" is expected to always
generate a QMP event, it seems like some ordering needs to be
enforced.

For the tests, the QMP input comes from a shell "here document" ('<<
EOF'), so I suppose stdin could read EOF and mark the chardev closed
before the QMP event is generated.  Before this change, QMP events
would still be generated and stdout would still be connected. Indeed,
chardev/char-fd.c:fd_chr_read() closes the chardev on stdio EOF
regardless of stdout state.

Regards,
Jason