Re: [PATCH v2 09/13] selftests/mm: skip uffd-wp-mremap if UFFD write-protect is unsupported

Sayali Patil
2026-03-13T14:26:19Z

On 12/03/26 18:20, David Hildenbrand (Arm) wrote:
> On 3/12/26 13:25, Sayali Patil wrote:
>> The uffd-wp-mremap test requires the UFFD_FEATURE_PAGEFAULT_FLAG_WP
>> capability. On systems where userfaultfd write-protect is
>> not supported, uffd_register() fails and the test reports failures.
>>
>> Check for the required feature at startup and skip the test when the
>> UFFD_FEATURE_PAGEFAULT_FLAG_WP capability is not present,
>> preventing false failures on unsupported configurations.
>>
>> Before patch:
>> running ./uffd-wp-mremap
>> ------------------------
>> [INFO] detected THP size: 256 KiB
>> [INFO] detected THP size: 512 KiB
>> [INFO] detected THP size: 1024 KiB
>> [INFO] detected THP size: 2048 KiB
>> [INFO] detected hugetlb page size: 2048 KiB
>> [INFO] detected hugetlb page size: 1048576 KiB
>> 1..24
>> [RUN] test_one_folio(size=65536, private=false, swapout=false,
>> hugetlb=false)
>> not ok 1 uffd_register() failed
>> [RUN] test_one_folio(size=65536, private=true, swapout=false,
>> hugetlb=false)
>> not ok 2 uffd_register() failed
>> [RUN] test_one_folio(size=65536, private=false, swapout=true,
>> hugetlb=false)
>> not ok 3 uffd_register() failed
>> [RUN] test_one_folio(size=65536, private=true, swapout=true,
>> hugetlb=false)
>> not ok 4 uffd_register() failed
>> [RUN] test_one_folio(size=262144, private=false, swapout=false,
>> hugetlb=false)
>> not ok 5 uffd_register() failed
>> [RUN] test_one_folio(size=524288, private=false, swapout=false,
>> hugetlb=false)
>> not ok 6 uffd_register() failed
>> .
>> .
>> .
>> Bail out! 24 out of 24 tests failed
>> Totals: pass:0 fail:24 xfail:0 xpass:0 skip:0 error:0
>> [FAIL]
>> not ok 1 uffd-wp-mremap # exit=1
>>
>> After patch:
>> running ./uffd-wp-mremap
>> ------------------------
>> 1..0 # SKIP uffd-wp feature not supported
>> [SKIP]
>> ok 1 uffd-wp-mremap # SKIP
>>
>> Acked-by: Zi Yan <ziy@nvidia.com>
>> Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
>> ---
>> tools/testing/selftests/mm/uffd-wp-mremap.c | 13 +++++++++++++
>> 1 file changed, 13 insertions(+)
>>
>> diff --git a/tools/testing/selftests/mm/uffd-wp-mremap.c b/tools/testing/selftests/mm/uffd-wp-mremap.c
>> index 17186d4a4147..73d53a4da389 100644
>> --- a/tools/testing/selftests/mm/uffd-wp-mremap.c
>> +++ b/tools/testing/selftests/mm/uffd-wp-mremap.c
>> @@ -19,6 +19,17 @@ static size_t thpsizes[20];
>> static int nr_hugetlbsizes;
>> static size_t hugetlbsizes[10];
>>
>> +static void uffd_wp_feature_supported(void)
> Likely that function should be called
>
> "check_uffd_wp_feature_supported()"
>
> Because right now it reads as if it would be returning a bool.
>
> Acked-by: David Hildenbrand (Arm) <david@kernel.org>
>
Thanks for the review. I'll rename it to
"check_uffd_wp_feature_supported()" in the next version.