selftests/rseq: Skip tests if time slice extensions are not available

commit 02b44d9 upstream.

Don't fail, skip the test if the extensions are not enabled at compile or
runtime.

Fixes: 830969e ("selftests/rseq: Implement time slice extension test")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://patch.msgid.link/20260428224427.597838491%40kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: KAGA-KOKO

tools/testing/selftests/rseq/slice_test.c

@@ -124,6 +124,13 @@ FIXTURE_SETUP(slice_ext)
 {
 	cpu_set_t affinity;
 
+	if (rseq_register_current_thread())
+		SKIP(return, "RSEQ not supported\n");
+
+	if (prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
+		  PR_RSEQ_SLICE_EXT_ENABLE, 0, 0))
+		SKIP(return, "Time slice extension not supported\n");
+
 	ASSERT_EQ(sched_getaffinity(0, sizeof(affinity), &affinity), 0);
 
 	/* Pin it on a single CPU. Avoid CPU 0 */
@@ -137,11 +144,6 @@ FIXTURE_SETUP(slice_ext)
 		break;
 	}
 
-	ASSERT_EQ(rseq_register_current_thread(), 0);
-
-	ASSERT_EQ(prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
-			PR_RSEQ_SLICE_EXT_ENABLE, 0, 0), 0);
-
 	self->noise_params.noise_nsecs = variant->noise_nsecs;
 	self->noise_params.sleep_nsecs = variant->sleep_nsecs;
 	self->noise_params.run = 1;