Re: [PATCH 4/4] iotests: Add regression test for issue 945

[Eric Blake <eblake@redhat.com>]

On Wed, Apr 27, 2022 at 01:40:57PM +0200, Hanna Reitz wrote:
> Create a VM with a BDS in an iothread, add -incoming defer to the
> command line, and then export this BDS via NBD.  Doing so should not
> fail an assertion.
> 
> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
> ---
>  .../tests/export-incoming-iothread            | 81 +++++++++++++++++++
>  .../tests/export-incoming-iothread.out        |  5 ++
>  2 files changed, 86 insertions(+)
>  create mode 100755 tests/qemu-iotests/tests/export-incoming-iothread
>  create mode 100644 tests/qemu-iotests/tests/export-incoming-iothread.out

The test looks sane, and appears to match the formula posted in issue
945.  When applying just patches 3-4 (skipping 1-2), './check
export-incoming-iothread' passed, but './check -qcow2
export-incoming-iothread' failed; so the image format is important.
And the failure was rather verbose, which is a GOOD thing - our
efforts to make the python framework point out abnormal exits is
working!

+WARNING:qemu.machine.machine:qemu received signal 6; command: "/home/eblake/qemu/build/tests/qemu-iotests/...
...
+Traceback (most recent call last):
+  File "/home/eblake/qemu/tests/qemu-iotests/tests/export-incoming-iothread", line 69, in test_export_add
+    result = self.vm.qmp('block-export-add', {
...
+  File "/home/eblake/qemu/python/qemu/qmp/qmp_client.py", line 463, in _reply
+    raise result
+qemu.qmp.qmp_client.ExecInterruptedError: Disconnected
+
+======================================================================
+ERROR: test_export_add (__main__.TestExportIncomingIothread)
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "/home/eblake/qemu/python/qemu/machine/machine.py", line 533, in _soft_shutdown
+    self.qmp('quit')
...
+qemu.qmp.protocol.StateError: QMPClient is disconnecting. Call disconnect() to return to IDLE state.
+
+During handling of the above exception, another exception occurred:
+
+Traceback (most recent call last):
+  File "/home/eblake/qemu/python/qemu/machine/machine.py", line 554, in _do_shutdown
+    self._soft_shutdown(timeout)
...
+  File "/home/eblake/qemu/python/qemu/qmp/protocol.py", line 968, in _readline
+    raise EOFError
+EOFError
+
+The above exception was the direct cause of the following exception:
+
+Traceback (most recent call last):
+  File "/home/eblake/qemu/tests/qemu-iotests/tests/export-incoming-iothread", line 54, in tearDown
+    self.vm.shutdown()
+  File "/home/eblake/qemu/python/qemu/machine/machine.py", line 583, in shutdown
+    self._do_shutdown(timeout)
+  File "/home/eblake/qemu/python/qemu/machine/machine.py", line 557, in _do_shutdown
+    raise AbnormalShutdown("Could not perform graceful shutdown") \
+qemu.machine.machine.AbnormalShutdown: Could not perform graceful shutdown
+
 ----------------------------------------------------------------------
 Ran 1 tests

-OK
+FAILED (errors=2)


Then applying patches 1-2 and repeating the test passed, so your test
is a good proof that we identified and fixed the problem at hand.

Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>

Given that it is visible with NBD, I'm happy to queue this series
through my tree if no one else grabs it first.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org