Re: [PATCH v3 03/10] selftests/mm: Skip uffd-wp-mremap if userfaultfd not available

On 28/02/25 10:24 pm, Brendan Jackman wrote:

It's obvious that this should fail in that case, but still, save the reader the effort of figuring out that they've run into this by just SKIPping

Signed-off-by: Brendan Jackman jackmanb@google.com

tools/testing/selftests/mm/uffd-wp-mremap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mm/uffd-wp-mremap.c b/tools/testing/selftests/mm/uffd-wp-mremap.c index 2c4f984bd73caa17e12b9f4a5bb71e7fdf5d8554..c2ba7d46c7b4581a3c32a6b6acd148e3e89c2172 100644 --- a/tools/testing/selftests/mm/uffd-wp-mremap.c +++ b/tools/testing/selftests/mm/uffd-wp-mremap.c @@ -182,7 +182,10 @@ static void test_one_folio(size_t size, bool private, bool swapout, bool hugetlb /* Register range for uffd-wp. */ if (userfaultfd_open(&features)) {

• ksft_test_result_fail("userfaultfd_open() failed\n");
  

• if (errno == ENOENT)
  

• 	ksft_test_result_skip("userfaultfd not available\n");
  

• else
  

• 	ksft_test_result_fail("userfaultfd_open() failed\n");
  

  goto out; } if (uffd_register(uffd, mem, size, false, true, false)) {

I think you are correct, just want to confirm whether "uffd not available" if and only if "errno == ENOENT" is true. That is, is it possible that errno can be something else and uffd is still not available, or errno can be ENOENT even if uffd is available.