Re: [PATCH for-11.1?] qemu-iotest 161: fix race

On Tue, Jul 28, 2026 at 12:40 PM Michael Tokarev <[email protected]> wrote:
>
> qemu-iotest 161 fails intermittedly due to a race condition:
>
> qemu:block / io-qcow2-161             ERROR            2.08s   exit status 1
> ――――――――――――――――――――――――――――――――――― ✀  ―――――――――――――――――――――――――――――――――――――
> stderr:
> --- tests/qemu-iotests/161.out
> +++ scratch/qcow2-file-161/161.out.bad
> @@ -34,6 +34,8 @@
>  *** Commit and then change an option on the backing file
>
>  Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=1048576
> +qemu-img: TEST_DIR/t.IMGFMT.base: Failed to get "write" lock
> +Is another process using the image [TEST_DIR/t.IMGFMT.base]?
>  Formatting 'TEST_DIR/t.IMGFMT.int', fmt=IMGFMT size=1048576 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
>  Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 backing_file=TEST_DIR/t.IMGFMT.int backing_fmt=IMGFMT
>  { 'execute': 'qmp_capabilities' }
>
> This test is run right after a previous test, where we've
> killed qemu process which holds the test image open.
> It looks like when the next test is started (with creating
> the image files), old qemu is still running, so we're racing
> with that qemu, and qemu-img is unable to lock the image file
> properly.
>
> We can add some `sleep $little-amount` here, but it is simpler
> and more reliable to just remove the image files, so that new
> ones are created.
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/2867
> Signed-off-by: Michael Tokarev <[email protected]>

Reviewed-by: Stefan Hajnoczi <[email protected]>