Test bpf_get_func_arg() and bpf_get_func_arg_cnt() for tp_btf. The code
is most copied from test1 and test2.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
---
 .../bpf/prog_tests/get_func_args_test.c       |  1 +
 .../selftests/bpf/progs/get_func_args_test.c  | 44 +++++++++++++++++++
 .../bpf/test_kmods/bpf_testmod-events.h       | 10 +++++
 .../selftests/bpf/test_kmods/bpf_testmod.c    |  4 ++
 4 files changed, 59 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
index 64a9c95d4acf..848fab952719 100644
--- a/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
@@ -33,6 +33,7 @@ void test_get_func_args_test(void)
 
 	ASSERT_EQ(topts.retval >> 16, 1, "test_run");
 	ASSERT_EQ(topts.retval & 0xffff, 1234 + 29, "test_run");
+	ASSERT_OK(trigger_module_test_read(1), "trigger_read");
 
 	ASSERT_EQ(skel->bss->test1_result, 1, "test1_result");
 	ASSERT_EQ(skel->bss->test2_result, 1, "test2_result");
diff --git a/tools/testing/selftests/bpf/progs/get_func_args_test.c b/tools/testing/selftests/bpf/progs/get_func_args_test.c
index e0f34a55e697..5b7233afef05 100644
--- a/tools/testing/selftests/bpf/progs/get_func_args_test.c
+++ b/tools/testing/selftests/bpf/progs/get_func_args_test.c
@@ -121,3 +121,47 @@ int BPF_PROG(fexit_test, int _a, int *_b, int _ret)
 	test4_result &= err == 0 && ret == 1234;
 	return 0;
 }
+
+__u64 test5_result = 0;
+SEC("tp_btf/bpf_testmod_fentry_test1_tp")
+int BPF_PROG(tp_test1)
+{
+	__u64 cnt = bpf_get_func_arg_cnt(ctx);
+	__u64 a = 0, z = 0;
+	__s64 err;
+
+	test5_result = cnt == 1;
+
+	err = bpf_get_func_arg(ctx, 0, &a);
+	test5_result &= err == 0 && ((int) a == 1);
+
+	/* not valid argument */
+	err = bpf_get_func_arg(ctx, 1, &z);
+	test5_result &= err == -EINVAL;
+
+	return 0;
+}
+
+__u64 test6_result = 0;
+SEC("tp_btf/bpf_testmod_fentry_test2_tp")
+int BPF_PROG(tp_test2)
+{
+	__u64 cnt = bpf_get_func_arg_cnt(ctx);
+	__u64 a = 0, b = 0, z = 0;
+	__s64 err;
+
+	test6_result = cnt == 2;
+
+	/* valid arguments */
+	err = bpf_get_func_arg(ctx, 0, &a);
+	test6_result &= err == 0 && (int) a == 2;
+
+	err = bpf_get_func_arg(ctx, 1, &b);
+	test6_result &= err == 0 && b == 3;
+
+	/* not valid argument */
+	err = bpf_get_func_arg(ctx, 2, &z);
+	test6_result &= err == -EINVAL;
+
+	return 0;
+}
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod-events.h b/tools/testing/selftests/bpf/test_kmods/bpf_testmod-events.h
index aeef86b3da74..45a5e41f3a92 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod-events.h
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod-events.h
@@ -63,6 +63,16 @@ BPF_TESTMOD_DECLARE_TRACE(bpf_testmod_test_writable_bare,
 	sizeof(struct bpf_testmod_test_writable_ctx)
 );
 
+DECLARE_TRACE(bpf_testmod_fentry_test1,
+	TP_PROTO(int a),
+	TP_ARGS(a)
+);
+
+DECLARE_TRACE(bpf_testmod_fentry_test2,
+	TP_PROTO(int a, u64 b),
+	TP_ARGS(a, b)
+);
+
 #endif /* _BPF_TESTMOD_EVENTS_H */
 
 #undef TRACE_INCLUDE_PATH
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
index bc07ce9d5477..f3698746f033 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
@@ -396,11 +396,15 @@ __weak noinline struct file *bpf_testmod_return_ptr(int arg)
 
 noinline int bpf_testmod_fentry_test1(int a)
 {
+	trace_bpf_testmod_fentry_test1_tp(a);
+
 	return a + 1;
 }
 
 noinline int bpf_testmod_fentry_test2(int a, u64 b)
 {
+	trace_bpf_testmod_fentry_test2_tp(a, b);
+
 	return a + b;
 }
 
-- 
2.52.0

> diff --git a/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
> index 64a9c95d4acf..848fab952719 100644
> --- a/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
> +++ b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
> @@ -33,6 +33,7 @@ void test_get_func_args_test(void)
>
>  	ASSERT_EQ(topts.retval >> 16, 1, "test_run");
>  	ASSERT_EQ(topts.retval & 0xffff, 1234 + 29, "test_run");
> +	ASSERT_OK(trigger_module_test_read(1), "trigger_read");
>
>  	ASSERT_EQ(skel->bss->test1_result, 1, "test1_result");
>  	ASSERT_EQ(skel->bss->test2_result, 1, "test2_result");
>  	ASSERT_EQ(skel->bss->test3_result, 1, "test3_result");
>  	ASSERT_EQ(skel->bss->test4_result, 1, "test4_result");

The trigger_module_test_read() call fires the new tracepoints which run the
tp_test1 and tp_test2 BPF programs. These programs set test5_result and
test6_result respectively. However, there are no assertions here to verify
that test5_result and test6_result equal 1.

Should there be:

    ASSERT_EQ(skel->bss->test5_result, 1, "test5_result");
    ASSERT_EQ(skel->bss->test6_result, 1, "test6_result");

Without these assertions, the test will pass even if the tp_btf
bpf_get_func_arg() functionality is broken.

> diff --git a/tools/testing/selftests/bpf/progs/get_func_args_test.c b/tools/testing/selftests/bpf/progs/get_func_args_test.c

[ ... ]

> +__u64 test5_result = 0;
> +SEC("tp_btf/bpf_testmod_fentry_test1_tp")
> +int BPF_PROG(tp_test1)
> +{

[ ... ]

> +__u64 test6_result = 0;
> +SEC("tp_btf/bpf_testmod_fentry_test2_tp")
> +int BPF_PROG(tp_test2)
> +{

These result variables are set by the BPF programs but never checked in the
test driver, as noted above.


---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

CI run summary: https://github.com/kernel-patches/bpf/actions/runs/21055137351