selftests/bpf: Add stacktrace ips test for fentry/fexit

Adding test that attaches fentry/fexitand verifies the
ORC stacktrace matches expected functions.

The test is only for ORC unwinder to keep it simple.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260126211837.472802-6-jolsa@kernel.org

Author: olsajiri

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

@@ -183,6 +183,53 @@ static void test_stacktrace_ips_kprobe(bool retprobe)
 	stacktrace_ips__destroy(skel);
 }
 
+static void test_stacktrace_ips_trampoline(bool retprobe)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	struct stacktrace_ips *skel;
+
+	skel = stacktrace_ips__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "stacktrace_ips__open_and_load"))
+		return;
+
+	if (!skel->kconfig->CONFIG_UNWINDER_ORC) {
+		test__skip();
+		goto cleanup;
+	}
+
+	if (retprobe) {
+		skel->links.fexit_test = bpf_program__attach_trace(skel->progs.fexit_test);
+		if (!ASSERT_OK_PTR(skel->links.fexit_test, "bpf_program__attach_trace"))
+			goto cleanup;
+	} else {
+		skel->links.fentry_test = bpf_program__attach_trace(skel->progs.fentry_test);
+		if (!ASSERT_OK_PTR(skel->links.fentry_test, "bpf_program__attach_trace"))
+			goto cleanup;
+	}
+
+	trigger_module_test_read(1);
+
+	load_kallsyms();
+
+	if (retprobe) {
+		check_stacktrace_ips(bpf_map__fd(skel->maps.stackmap), skel->bss->stack_key, 4,
+				     ksym_get_addr("bpf_testmod_stacktrace_test_3"),
+				     ksym_get_addr("bpf_testmod_stacktrace_test_2"),
+				     ksym_get_addr("bpf_testmod_stacktrace_test_1"),
+				     ksym_get_addr("bpf_testmod_test_read"));
+	} else {
+		check_stacktrace_ips(bpf_map__fd(skel->maps.stackmap), skel->bss->stack_key, 5,
+				     ksym_get_addr("bpf_testmod_stacktrace_test"),
+				     ksym_get_addr("bpf_testmod_stacktrace_test_3"),
+				     ksym_get_addr("bpf_testmod_stacktrace_test_2"),
+				     ksym_get_addr("bpf_testmod_stacktrace_test_1"),
+				     ksym_get_addr("bpf_testmod_test_read"));
+	}
+
+cleanup:
+	stacktrace_ips__destroy(skel);
+}
+
 static void __test_stacktrace_ips(void)
 {
 	if (test__start_subtest("kprobe_multi"))
@@ -195,6 +242,10 @@ static void __test_stacktrace_ips(void)
 		test_stacktrace_ips_kprobe(false);
 	if (test__start_subtest("kretprobe"))
 		test_stacktrace_ips_kprobe(true);
+	if (test__start_subtest("fentry"))
+		test_stacktrace_ips_trampoline(false);
+	if (test__start_subtest("fexit"))
+		test_stacktrace_ips_trampoline(true);
 }
 #else
 static void __test_stacktrace_ips(void)

tools/testing/selftests/bpf/progs/stacktrace_ips.c

@@ -53,4 +53,24 @@ int rawtp_test(void *ctx)
 	return 0;
 }
 
+SEC("fentry/bpf_testmod_stacktrace_test")
+int fentry_test(struct pt_regs *ctx)
+{
+	/*
+	 * Skip 2 bpf_program/trampoline stack entries:
+	 * - bpf_prog_bd1f7a949f55fb03_fentry_test
+	 * - bpf_trampoline_182536277701
+	 */
+	stack_key = bpf_get_stackid(ctx, &stackmap, 2);
+	return 0;
+}
+
+SEC("fexit/bpf_testmod_stacktrace_test")
+int fexit_test(struct pt_regs *ctx)
+{
+	/* Skip 2 bpf_program/trampoline stack entries, check fentry_test. */
+	stack_key = bpf_get_stackid(ctx, &stackmap, 2);
+	return 0;
+}
+
 char _license[] SEC("license") = "GPL";