selftests/bpf: Add test for attaching kprobe with long event names

This test verifies that attaching kprobe/kretprobe with long event names
does not trigger EINVAL errors.

Signed-off-by: Feng Yang <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

Author: kknjh

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

@@ -168,6 +168,39 @@ static void test_attach_uprobe_long_event_name(void)
 	test_attach_probe_manual__destroy(skel);
 }
 
+/* attach kprobe/kretprobe long event name testings */
+static void test_attach_kprobe_long_event_name(void)
+{
+	DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, kprobe_opts);
+	struct bpf_link *kprobe_link, *kretprobe_link;
+	struct test_attach_probe_manual *skel;
+
+	skel = test_attach_probe_manual__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_kprobe_manual_open_and_load"))
+		return;
+
+	/* manual-attach kprobe/kretprobe */
+	kprobe_opts.attach_mode = PROBE_ATTACH_MODE_LEGACY;
+	kprobe_opts.retprobe = false;
+	kprobe_link = bpf_program__attach_kprobe_opts(skel->progs.handle_kprobe,
+						      "bpf_testmod_looooooooooooooooooooooooooooooong_name",
+						      &kprobe_opts);
+	if (!ASSERT_OK_PTR(kprobe_link, "attach_kprobe_long_event_name"))
+		goto cleanup;
+	skel->links.handle_kprobe = kprobe_link;
+
+	kprobe_opts.retprobe = true;
+	kretprobe_link = bpf_program__attach_kprobe_opts(skel->progs.handle_kretprobe,
+							 "bpf_testmod_looooooooooooooooooooooooooooooong_name",
+							 &kprobe_opts);
+	if (!ASSERT_OK_PTR(kretprobe_link, "attach_kretprobe_long_event_name"))
+		goto cleanup;
+	skel->links.handle_kretprobe = kretprobe_link;
+
+cleanup:
+	test_attach_probe_manual__destroy(skel);
+}
+
 static void test_attach_probe_auto(struct test_attach_probe *skel)
 {
 	struct bpf_link *uprobe_err_link;
@@ -371,6 +404,8 @@ void test_attach_probe(void)
 
 	if (test__start_subtest("uprobe-long_name"))
 		test_attach_uprobe_long_event_name();
+	if (test__start_subtest("kprobe-long_name"))
+		test_attach_kprobe_long_event_name();
 
 cleanup:
 	test_attach_probe__destroy(skel);

tools/testing/selftests/bpf/test_kmods/bpf_testmod.c

@@ -134,6 +134,10 @@ bpf_testmod_test_arg_ptr_to_struct(struct bpf_testmod_struct_arg_1 *a) {
 	return bpf_testmod_test_struct_arg_result;
 }
 
+__weak noinline void bpf_testmod_looooooooooooooooooooooooooooooong_name(void)
+{
+}
+
 __bpf_kfunc void
 bpf_testmod_test_mod_kfunc(int i)
 {