Re: [PATCH v3] selftests: harness: Mark test fixture objects __maybe_unused

[Kees Cook <kees@kernel.org>]

On Tue, Jul 14, 2026 at 09:24:36AM -0700, David Matlack wrote:
> On Mon, Jul 6, 2026 at 11:32 AM David Matlack <dmatlack@google.com> wrote:
> >
> > Mark _##fixture_name##_##test_name##_object __maybe_unused since it may
> > not ever be read. This pointer is only read in XFAIL_ADD(), which tests
> > are not required to use.
> >
> > clang made a change to -Wunused-but-set-variable (split out into its own
> > subwarning, -Wunused-but-set-global) that causes this warning to be
> > emitted for various selftests and can be upgraded to an error in
> > selftest that set -Werror.
> >
> > VFIO selftests have been broken since commit ff556bd98348 ("vfio:
> > selftests: Add -Wall and -Werror to the Makefile"), and the net
> > selftests builds have been noisy due to -Wall.
> >
> > Fixes: 24cf65a62266 ("selftests/harness: Share _metadata between forked processes")
> > Reported-by: Kuniyuki Iwashima <kuniyu@google.com>
> > Reported-by: Aaron Lewis <aaronlewis@google.com>
> > Reviewed-by: Alex Williamson <alex@shazbot.org>
> > Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
> > Signed-off-by: David Matlack <dmatlack@google.com>
> 
> Kees and Shuah, is it ok if Alex takes this through the VFIO tree? [1]
> This fixes a bug exposed by recent VFIO selftests commit ff556bd98348
> ("vfio: selftests: Add -Wall and -Werror to the Makefile").
> 
> [1] https://lore.kernel.org/linux-kselftest/20260630165244.0d013bbc@shazbot.org/

Yeah, please do. This has ample review. :)

-- 
Kees Cook