On 2021/12/20 0:09, kernel test robot wrote:
>     @@ -13,3 +13,5 @@
>      --- clean
>      --- umount ext2 on xfs
>      --- umount xfs
>     +!!! umount xfs failed
>     +(see /lkp/benchmarks/xfstests/results//xfs/049.full for details)
>     ...
>     (Run 'diff -u /lkp/benchmarks/xfstests/tests/xfs/049.out /lkp/benchmarks/xfstests/results//xfs/049.out.bad'  to see the entire diff)

Yes, we know this race condition can happen.

https://lkml.kernel.org/r/16c7d304-60ef-103f-1b2c-8592b48f47c6@i-love.sakura.ne.jp
https://lkml.kernel.org/r/YaYfu0H2k0PSQL6W@infradead.org

Should we try to wait for autoclear operation to complete?