Re: [PATCH] selftests/mm: mremap_test: handle ENOSYS for userfaultfd and add missing newlines

[Sarthak Sharma]

Hi Park Tae-sun!

On 9/22/26 12:21 PM, Park Tae-sun wrote:
> When running mremap_test on a kernel built without CONFIG_USERFAULTFD,
> test 26 fails:
> 
>     userfaultfd: Function not implemented
>     not ok 26 mremap move multiple invalid vmas
> 
> This happens because mremap_move_multi_invalid_vmas() only checks for
> EPERM, so ENOSYS is treated as an unexpected failure instead of being
> skipped.
> 
> In addition, ksft_test_result_skip() in both
> mremap_move_multi_invalid_vmas() and its fallback stub is missing a
> trailing newline, which causes the subsequent TAP summary count to get
> stuck on the same line:
> 
>     ok 26 # SKIP ... - missing uffd# 1 skipped test(s) detected...
> 
> Fix this following the switch pattern in guard-regions.c (lines 1498-1506):
> check for EPERM (advising running as root) and ENOSYS (missing uffd), move
> perror() to default so expected skips don't print noise to stderr, and add
> the missing '\n' to both skip strings.

Thanks for the fix, but I have posted a series of patches already [1]
which include skipping incase of ENOSYS and fixing the newline issue in
ksft_test_result_skip(). If it is okay with you, can we go ahead with my
patches since it solves some other issues as well?

[1]
https://lore.kernel.org/all/20260917111951.188266-1-sarthak.sharma@xxxxxxx/