On Thu, Aug 07, 2025 at 08:00:42PM +0800, Wake Liu wrote:
> The futex tests `futex_wait.c` and `futex_waitv.c` rely on the `shmget()`
> syscall, which may not be available if the kernel is built without
> System V IPC support (CONFIG_SYSVIPC=n). This can lead to test
> failures on such systems.
>
> This patch modifies the tests to check for `shmget()` support at
> runtime by calling it and checking for an `ENOSYS` error. If `shmget()`
> is not supported, the tests are skipped with a clear message,
> improving the user experience and preventing false negatives.
>
> This approach is more robust than relying on compile-time checks and
> ensures that the tests run only when the required kernel features are
> present.
>
> Signed-off-by: Wake Liu <wa...@google.com>
> ---
> .../selftests/futex/functional/futex_wait.c | 49 +++++++------
> .../selftests/futex/functional/futex_waitv.c | 73 ++++++++++++-------
> 2 files changed, 73 insertions(+), 49 deletions(-)
>
> diff --git a/tools/testing/selftests/futex/functional/futex_wait.c
> b/tools/testing/selftests/futex/functional/futex_wait.c
> index 685140d9b93d..17a465313a59 100644
> --- a/tools/testing/selftests/futex/functional/futex_wait.c
> +++ b/tools/testing/selftests/futex/functional/futex_wait.c
> @@ -48,7 +48,7 @@ static void *waiterfn(void *arg)
> int main(int argc, char *argv[])
> {
> int res, ret = RET_PASS, fd, c, shm_id;
> - u_int32_t f_private = 0, *shared_data;
> + u_int32_t f_private = 0, *shared_data = NULL;
> unsigned int flags = FUTEX_PRIVATE_FLAG;
> pthread_t waiter;
> void *shm;
> @@ -96,32 +96,35 @@ int main(int argc, char *argv[])
> /* Testing an anon page shared memory */
> shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666);
> if (shm_id < 0) {
> - perror("shmget");
> - exit(1);
> - }
> -
> - shared_data = shmat(shm_id, NULL, 0);
> + if (errno == ENOSYS) {
> + ksft_test_result_skip("Kernel does not support System V
> shared memory\n");
> + } else {
> + ksft_test_result_fail("shmget() failed with error:
> %s\n", strerror(errno));
> + ret = RET_FAIL;
kselftest.h is already keeping track of the failure status.
Just call ksft_finished() at the end.
Also the whole perror()/exit(1) pattern doesn't really make sense in a
kselftest.
> + }
> + } else {
> + shared_data = shmat(shm_id, NULL, 0);
(...)
