[PATCH v3 bpf-next 3/3] selftests/bpf: Add test for attaching kprobe with long event names

Feng Yang
2025-04-14T09:35:15Z

From: Feng Yang <yangfeng@kylinos.cn>

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

Signed-off-by: Feng Yang <yangfeng@kylinos.cn>
---
.../selftests/bpf/prog_tests/attach_probe.c | 35 +++++++++++++++++++
.../selftests/bpf/test_kmods/bpf_testmod.c | 5 +++
.../bpf/test_kmods/bpf_testmod_kfunc.h | 2 ++
3 files changed, 42 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
index 9b7f36f39c32..633b5eb4379b 100644
--- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c
+++ b/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_kfunc_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_kfunc_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);
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
index f38eaf0d35ef..439f6c2b2456 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
@@ -1053,6 +1053,10 @@ __bpf_kfunc int bpf_kfunc_st_ops_inc10(struct st_ops_args *args)
return args->a;
}

+__bpf_kfunc void bpf_kfunc_looooooooooooooooooooooooooooooong_name(void)
+{
+}
+
BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
@@ -1093,6 +1097,7 @@ BTF_ID_FLAGS(func, bpf_kfunc_st_ops_test_prologue, KF_TRUSTED_ARGS | KF_SLEEPABL
BTF_ID_FLAGS(func, bpf_kfunc_st_ops_test_epilogue, KF_TRUSTED_ARGS | KF_SLEEPABLE)
BTF_ID_FLAGS(func, bpf_kfunc_st_ops_test_pro_epilogue, KF_TRUSTED_ARGS | KF_SLEEPABLE)
BTF_ID_FLAGS(func, bpf_kfunc_st_ops_inc10, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_kfunc_looooooooooooooooooooooooooooooong_name)
BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids)

static int bpf_testmod_ops_init(struct btf *btf)
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h
index b58817938deb..e5b833140418 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h
@@ -159,4 +159,6 @@ void bpf_kfunc_trusted_task_test(struct task_struct *ptr) __ksym;
void bpf_kfunc_trusted_num_test(int *ptr) __ksym;
void bpf_kfunc_rcu_task_test(struct task_struct *ptr) __ksym;

+void bpf_kfunc_looooooooooooooooooooooooooooooong_name(void) __ksym;
+
#endif /* _BPF_TESTMOD_KFUNC_H */
--
2.43.0