Re: QEMU iotest 267 failure / assertion in migration code

[Thomas Huth <thuth@redhat.com>]

On 18/01/2023 19.02, Dr. David Alan Gilbert wrote:
> * Thomas Huth (thuth@redhat.com) wrote:
>>
>>   Hi!
>>
>> I just ran "make check" in a build directory where I did
>> not compile qemu-system-x86_64, and got a failure with
>> iotest 267.
>>
>> Re-running the "check" script directly got me some more
>> information:
>>
>> $ ./check -qcow2 267
>> QEMU          -- "/tmp/qemu/tests/qemu-iotests/../../qemu-system-alpha" -nodefaults -display none -accel qtest
>> QEMU_IMG      -- "/tmp/qemu/tests/qemu-iotests/../../qemu-img"
>> QEMU_IO       -- "/tmp/qemu/tests/qemu-iotests/../../qemu-io" --cache writeback --aio threads -f qcow2
>> QEMU_NBD      -- "/tmp/qemu/tests/qemu-iotests/../../qemu-nbd"
>> IMGFMT        -- qcow2
>> IMGPROTO      -- file
>> PLATFORM      -- Linux/x86_64 thuth 4.18.0-425.3.1.el8.x86_64
>> TEST_DIR      -- /tmp/qemu/tests/qemu-iotests/scratch
>> SOCK_DIR      -- /tmp/tmp_qbcjhsu
>> GDB_OPTIONS   --
>> VALGRIND_QEMU --
>> PRINT_QEMU_OUTPUT --
>>
>> 267   fail       [18:39:41] [18:39:44]   3.5s                 output mismatch (see /tmp/qemu/tests/qemu-iotests/scratch/267.out.bad)
>> --- .../qemu/tests/qemu-iotests/267.out
>> +++ /tmp/qemu/tests/qemu-iotests/scratch/267.out.bad
>> @@ -31,23 +31,23 @@
>>   Testing: -drive driver=IMGFMT,file=TEST_DIR/t.IMGFMT,if=none
>>   QEMU X.Y.Z monitor - type 'help' for more information
>>   (qemu) savevm snap0
>> -(qemu) info snapshots
>> -List of snapshots present on all disks:
>> -ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
>> ---        snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
>> -(qemu) loadvm snap0
>> -(qemu) quit
>> +QEMU_PROG: ../../qemu/migration/ram.c:874: pss_find_next_dirty: Assertion `pss->host_page_end' failed.
> 
> I don't understand how that can trigger - it needs investigating as a
> bug.

I've created a ticket so we don't forget:

https://gitlab.com/qemu-project/qemu/-/issues/1456

>> +./common.rc: line 181: 1903770 Aborted                 (core dumped) ( if [ -n "${QEMU_NEED_PID}" ]; then
>> +    echo $BASHPID > "${QEMU_TEST_DIR}/qemu-${_QEMU_HANDLE}.pid";
>> +fi; GDB=""; if [ -n "${GDB_OPTIONS}" ]; then
>> +    GDB="gdbserver ${GDB_OPTIONS}";
>> +fi; VALGRIND_QEMU="${VALGRIND_QEMU_VM}" _qemu_proc_exec "${VALGRIND_LOGFILE}" $GDB "$QEMU_PROG" $QEMU_OPTIONS "$@" )
>>
>>
>> Looks like this test does not work if the main machine
>> of the selected QEMU binary does not support migration?
> 
> Why doesn't it support migration?

Hmm, maybe I just got that wrong and it's really just the problem that the 
qemu-system-alpha is crashing.

  Thomas