[PATCH bpf-next 7/8] selftests/bpf: Add a test to verify call_get_func_ip compatibility enforcement

[Leon Hwang <leon.hwang@linux.dev>]

Add prog_array coverage for tracing programs that differ in
bpf_get_func_ip() dependency.

The test verifies one-way enforcement: !call_get_func_ip programs
cannot tail-call call_get_func_ip programs.

Assisted-by: Codex:gpt-5.3-codex
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
 .../bpf/prog_tests/get_func_ip_test.c         | 46 +++++++++++++++++++
 .../selftests/bpf/progs/get_func_ip_test.c    |  6 +++
 2 files changed, 52 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c b/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c
index 7772a0f288d3..670457d4e159 100644
--- a/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c
@@ -139,3 +139,49 @@ void test_get_func_ip_test(void)
 	test_function_entry();
 	test_function_body();
 }
+
+static void test_prog_array_call_get_func_ip_compat(void)
+{
+	__u32 key = 0, with_get_func_ip_fd, without_get_func_ip_fd;
+	struct get_func_ip_test *skel = NULL;
+	int map_fd = -1, err;
+
+	skel = get_func_ip_test__open();
+	if (!ASSERT_OK_PTR(skel, "get_func_ip_test__open"))
+		return;
+
+	err = get_func_ip_test__load(skel);
+	if (!ASSERT_OK(err, "get_func_ip_test__load"))
+		goto cleanup;
+
+	with_get_func_ip_fd = bpf_program__fd(skel->progs.test1);
+	without_get_func_ip_fd = bpf_program__fd(skel->progs.test1_dummy);
+	if (!ASSERT_GE(with_get_func_ip_fd, 0, "with_get_func_ip_fd"))
+		goto cleanup;
+	if (!ASSERT_GE(without_get_func_ip_fd, 0, "without_get_func_ip_fd"))
+		goto cleanup;
+
+	map_fd = bpf_map_create(BPF_MAP_TYPE_PROG_ARRAY, NULL, sizeof(key),
+				sizeof(__u32), 1, NULL);
+	if (!ASSERT_GE(map_fd, 0, "bpf_map_create"))
+		goto cleanup;
+
+	err = bpf_map_update_elem(map_fd, &key, &without_get_func_ip_fd, BPF_ANY);
+	if (!ASSERT_OK(err, "bpf_map_update_elem success"))
+		goto cleanup;
+
+	err = bpf_map_update_elem(map_fd, &key, &with_get_func_ip_fd, BPF_ANY);
+	if (!ASSERT_ERR(err, "bpf_map_update_elem failure"))
+		goto cleanup;
+	ASSERT_EQ(errno, EINVAL, "bpf_map_update_elem errno");
+
+cleanup:
+	if (map_fd >= 0)
+		close(map_fd);
+	get_func_ip_test__destroy(skel);
+}
+
+void test_get_func_ip_test_prog_map_compatible(void)
+{
+	test_prog_array_call_get_func_ip_compat();
+}
diff --git a/tools/testing/selftests/bpf/progs/get_func_ip_test.c b/tools/testing/selftests/bpf/progs/get_func_ip_test.c
index 45eaa54d1ac7..6a7d306af96e 100644
--- a/tools/testing/selftests/bpf/progs/get_func_ip_test.c
+++ b/tools/testing/selftests/bpf/progs/get_func_ip_test.c
@@ -32,6 +32,12 @@ int BPF_PROG(test1, int a)
 	return 0;
 }
 
+SEC("fentry/bpf_fentry_test1")
+int BPF_PROG(test1_dummy, int a)
+{
+	return 0;
+}
+
 __u64 test2_result = 0;
 SEC("fexit/bpf_fentry_test2")
 int BPF_PROG(test2, int a)
-- 
2.52.0