selftests/futex: Skip tests if shmget unsupported

On systems where the shmget() syscall is not supported, tests like
anon_page and shared_waitv will fail. Skip these tests in such cases to
allow the rest of the test suite to run.

Signed-off-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251016162009.3270784-1-cmllamas@google.com

Author: Carlos Llamas

tools/testing/selftests/futex/functional/futex_wait.c

@@ -71,6 +71,8 @@ TEST(anon_page)
 	/* Testing an anon page shared memory */
 	shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666);
 	if (shm_id < 0) {
+		if (errno == ENOSYS)
+			ksft_exit_skip("shmget syscall not supported\n");
 		perror("shmget");
 		exit(1);
 	}

tools/testing/selftests/futex/functional/futex_waitv.c

@@ -86,6 +86,8 @@ TEST(shared_waitv)
 		int shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666);
 
 		if (shm_id < 0) {
+			if (errno == ENOSYS)
+				ksft_exit_skip("shmget syscall not supported\n");
 			perror("shmget");
 			exit(1);
 		}