selftests/bpf: Migrate fexit_noreturns case into tracing_failure test suite

Delete fexit_noreturns.c files and migrate the cases into
tracing_failure.c files.

The result:

 $ tools/testing/selftests/bpf/test_progs -t tracing_failure/fexit_noreturns
 torvalds#467/4   tracing_failure/fexit_noreturns:OK
 torvalds#467     tracing_failure:OK
 Summary: 1/1 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: KaFai Wan <[email protected]>

Author: mannkafai

tools/testing/selftests/bpf/prog_tests/fexit_noreturns.c

@@ -28,37 +28,54 @@ static void test_bpf_spin_lock(bool is_spin_lock)
 	tracing_failure__destroy(skel);
 }
 
-static void test_tracing_deny(void)
+static void test_tracing_fail_prog(const char *prog_name, const char *exp_msg)
 {
 	struct tracing_failure *skel;
+	struct bpf_program *prog;
 	char log_buf[256];
-	int btf_id, err;
-
-	/* migrate_disable depends on CONFIG_SMP */
-	btf_id = libbpf_find_vmlinux_btf_id("migrate_disable", BPF_TRACE_FENTRY);
-	if (btf_id <= 0) {
-		test__skip();
-		return;
-	}
+	int err;
 
 	skel = tracing_failure__open();
 	if (!ASSERT_OK_PTR(skel, "tracing_failure__open"))
 		return;
 
-	bpf_program__set_autoload(skel->progs.tracing_deny, true);
-	bpf_program__set_log_buf(skel->progs.tracing_deny, log_buf, sizeof(log_buf));
+	prog = bpf_object__find_program_by_name(skel->obj, prog_name);
+	if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
+		goto out;
+
+	bpf_program__set_autoload(prog, true);
+	bpf_program__set_log_buf(prog, log_buf, sizeof(log_buf));
 
 	err = tracing_failure__load(skel);
 	if (!ASSERT_ERR(err, "tracing_failure__load"))
 		goto out;
 
-	ASSERT_HAS_SUBSTR(log_buf,
-			  "Attaching tracing programs to function 'migrate_disable' is rejected.",
-			  "log_buf");
+	ASSERT_HAS_SUBSTR(log_buf, exp_msg, "log_buf");
 out:
 	tracing_failure__destroy(skel);
 }
 
+static void test_tracing_deny(void)
+{
+	int btf_id;
+
+	/* migrate_disable depends on CONFIG_SMP */
+	btf_id = libbpf_find_vmlinux_btf_id("migrate_disable", BPF_TRACE_FENTRY);
+	if (btf_id <= 0) {
+		test__skip();
+		return;
+	}
+
+	test_tracing_fail_prog("tracing_deny",
+			       "Attaching tracing programs to function 'migrate_disable' is rejected.");
+}
+
+static void test_fexit_noreturns(void)
+{
+	test_tracing_fail_prog("fexit_noreturns",
+			       "Attaching fexit/fmod_ret to __noreturn function 'do_exit' is rejected.");
+}
+
 void test_tracing_failure(void)
 {
 	if (test__start_subtest("bpf_spin_lock"))
@@ -67,4 +84,6 @@ void test_tracing_failure(void)
 		test_bpf_spin_lock(false);
 	if (test__start_subtest("tracing_deny"))
 		test_tracing_deny();
+	if (test__start_subtest("fexit_noreturns"))
+		test_fexit_noreturns();
 }

tools/testing/selftests/bpf/prog_tests/tracing_failure.c

@@ -24,3 +24,9 @@ int BPF_PROG(tracing_deny)
 {
 	return 0;
 }
+
+SEC("?fexit/do_exit")
+int BPF_PROG(fexit_noreturns)
+{
+	return 0;
+}