Re: [hugetlbfs] 3a47c54f09: kernel-selftests.vm.run_vmtests.sh../userfaultfd_hugetlb_256_32.fail

From: Mike Kravetz
Date: Fri Oct 21 2022 - 14:58:18 EST


On 10/21/22 16:04, kernel test robot wrote:
> Hi Mike,
>
> We noticed below commit reverts some hugetlb related code in fault path,
> and we happened to catch a "userfaultfd hugetlb" selftests failure on
> this commit. Could you please help check if this is an expected result?
>
> The commit message mentions about:
>
> "In subsequent patches, a new synchronization mechanism will be added to
> coordinate pmd sharing and eliminate this race."
>
> We noticed this failure still exists on the latest mainline head
> e35184f321518 ("Merge tag 'drm-fixes-2022-10-21' of git://anongit.freedesktop.org/drm/drm")
>
> Please kindly let us know if you'd like us to keep tracking this issue on
> mainline, or please feel free to ignore this report if this issue is not
> that important.

Fixed with commit 2ea7ff1e39cb "mm/hugetlb: fix race condition of uffd
missing/minor handling"
--
Mike Kravetz