Re: [PATCH 1/1] tools feature gettid: Undef _GNU_SOURCE before defining it

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Mon, Sep 28, 2026 at 08:12:45AM -0700, Ian Rogers wrote:
> On Mon, Sep 28, 2026 at 5:02 AM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
> >
> > Since most of tools/build/feature/test-*.c feature tests are included in
> > tools/build/feature/test-all.c, we can't just define _GNU_SOURCE as it
> > may already been defined and this will break the build with:
> >
> >   acme@alta:~$ cat /tmp/build/perf-tools-next/feature/test-all.make.output
> >   In file included from test-all.c:26:
> >   test-gettid.c:3:9: error: "_GNU_SOURCE" redefined [-Werror]
> >       3 | #define _GNU_SOURCE
> >         |         ^~~~~~~~~~~
> >   In file included from /usr/include/python3.13/pyconfig.h:9,
> >                    from /usr/include/python3.13/Python.h:14,
> >                    from test-python-module.c:2,
> >                    from test-all.c:14:
> >   /usr/include/aarch64-linux-gnu/python3.13/pyconfig.h:1810:10: note: this is the location of the previous definition
> >    1810 | # define _GNU_SOURCE 1
> >         |          ^~~~~~~~~~~
> >   cc1: all warnings being treated as errors
> >   acme@alta:~$
> >
> > I.e. pyconfig.h is included by the new test-python-module.c, that is at
> > the start of test-all.c, defines _GNU_SOURCE, noticed on Debian 13
> > (/usr/include/aarch64-linux-gnu/python3.13/pyconfig.h, libpython
> > 3.13.5-2+deb13u5), and then test-all.c includes test-gettid.c that was
> > defining it as well, undef it first as does several other tests.
> >
> > Fixes: 1b7e0280e247b93d ("perf Makefile: Update Python script installation path")
> > Cc: Ian Rogers <irogers@google.com>
> > Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> Reviewed-by: Ian Rogers <irogers@google.com>

Thanks, applied to perf-tools-next, for v7.4.

- Arnaldo