Re: QEMU iotest 267 failure / assertion in migration code

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* 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.

> +./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?

> Should we remove this test from the "auto" group?
> 
> Anyway, QEMU should also not trigger an assertion, so this
> sounds like another bug?

Yeh; that's a weird failure.

(Alpha page size seems to be 8k from what I can tell; which should be
fine, if you're running on an x86 host)

Dave

>  Thomas
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK