io-qcow2-copy-before-write intermittent failure (ppc64 host)

[Peter Maydell]

ppc64 host:

737/761 qemu:block / io-qcow2-copy-before-write
           ERROR           6.77s   exit status 1
――――――――――――――――――――――――――――――――――――― ✀  ―――――――――――――――――――――――――――――――――――――
stderr:
--- /home/pm215/qemu/tests/qemu-iotests/tests/copy-before-write.out
+++ 
/home/pm215/qemu/build/all/scratch/qcow2-file-copy-before-write/copy-before-write.out.bad
@@ -1,5 +1,21 @@
-....
+...F
+======================================================================
+FAIL: test_timeout_break_snapshot
(__main__.TestCbwError.test_timeout_break_snapshot)
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "/home/pm215/qemu/tests/qemu-iotests/tests/copy-before-write",
line 210, in test_timeout_break_snapshot
+    self.assertEqual(log, """\
+AssertionError: 'wrot[195 chars]read 1048576/1048576 bytes at offset
0\n1 MiB,[46 chars]c)\n' != 'wrot[195 chars]read failed: Permission
denied\n'
+  wrote 524288/524288 bytes at offset 0
+  512 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+  wrote 524288/524288 bytes at offset 524288
+  512 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
++ read failed: Permission denied
+- read 1048576/1048576 bytes at offset 0
+- 1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+
 ----------------------------------------------------------------------
 Ran 4 tests

-OK
+FAILED (failures=1)

(test program exited with status code 1)

This is an intermittent; we've seen it before on this host:
https://lore.kernel.org/qemu-devel/CAFEAcA8ipWKpv09pyQWNQBiUhd2JYM=sn4qv2YBen-pN3beU0Q@mail.gmail.com/


-- PMM