Re: [PATCH RESEND 2/9] selftests/mm: mremap_test: skip test when userfaultfd is unavailable

[David Hildenbrand (Arm)]

On 9/24/26 07:00, Sarthak Sharma wrote:
> The userfaultfd syscall can return ENOSYS even when __NR_userfaultfd is
> defined by the architecture headers, for example when the kernel is
> built without CONFIG_USERFAULTFD. The test currently skips for EPERM
> when the caller lacks permission to use userfaultfd but treats
> ENOSYS as a failure.
> 
> Handle ENOSYS like EPERM and skip the mremap_move_multi_invalid_vmas()
> test when userfaultfd syscall is not implemented.
> 
> Fixes: 742d3663a577 ("selftests/mm: add test for invalid multi VMA operations")
> Signed-off-by: Sarthak Sharma <sarthak.sharma@xxxxxxx>
> ---
>  tools/testing/selftests/mm/mremap_test.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/mm/mremap_test.c b/tools/testing/selftests/mm/mremap_test.c
> index 5532d3151ed0..a5813a5e8f5b 100644
> --- a/tools/testing/selftests/mm/mremap_test.c
> +++ b/tools/testing/selftests/mm/mremap_test.c
> @@ -721,7 +721,7 @@ static void mremap_move_multi_invalid_vmas(FILE *maps_fp,
>  	if (uffd == -1) {
>  		err = errno;
>  		ksft_perror("userfaultfd");

Should we rather move that below the if? Doesn't quite make sense to print the
error if we are skipping and printing a proper message.

Maybe that should go into the previous patch?

> -		if (err == EPERM) {
> +		if (err == EPERM || err == ENOSYS) {
>  			ksft_test_result_skip("%s - missing uffd\n", test_name);
>  			return;
>  		}

Apart from that LGTM.

Acked-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>

-- 
Cheers,

David