Re: [PATCH bpf-next v3 3/3] selftests/bpf: Add libbpf_probe_bpf_kfunc API selftests

Jiri Olsa
2025-01-24T16:27:31Z

On Fri, Jan 24, 2025 at 10:44:11PM +0800, Tao Chen wrote:
> Add selftests for prog_kfunc feature probing.
> ./test_progs -t libbpf_probe_kfuncs
> #153 libbpf_probe_kfuncs:OK
> Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
>
> Signed-off-by: Tao Chen <chen.dylane@gmail.com>
> ---
> .../selftests/bpf/prog_tests/libbpf_probes.c | 35 +++++++++++++++++++
> 1 file changed, 35 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> index 4ed46ed58a7b..d9d69941f694 100644
> --- a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> @@ -126,3 +126,38 @@ void test_libbpf_probe_helpers(void)
> ASSERT_EQ(res, d->supported, buf);
> }
> }
> +
> +void test_libbpf_probe_kfuncs(void)
> +{
> + int ret, kfunc_id;
> + char *kfunc = "bpf_cpumask_create";
> + struct btf *btf;
> +
> + btf = btf__parse("/sys/kernel/btf/vmlinux", NULL);
> + if (!ASSERT_OK_PTR(btf, "btf_parse"))
> + return;
> +
> + kfunc_id = btf__find_by_name_kind(btf, kfunc, BTF_KIND_FUNC);
> + if (!ASSERT_GT(kfunc_id, 0, kfunc))
> + goto cleanup;
> +
> + /* prog BPF_PROG_TYPE_SYSCALL supports kfunc bpf_cpumask_create */
> + ret = libbpf_probe_bpf_kfunc(BPF_PROG_TYPE_SYSCALL, kfunc_id, 0, NULL);
> + ASSERT_EQ(ret, 1, kfunc);
> +
> + /* prog BPF_PROG_TYPE_KPROBE does not support kfunc bpf_cpumask_create */
> + ret = libbpf_probe_bpf_kfunc(BPF_PROG_TYPE_KPROBE, kfunc_id, 0, NULL);
> + ASSERT_EQ(ret, 0, kfunc);
> +
> + /* invalid kfunc id */
> + ret = libbpf_probe_bpf_kfunc(BPF_PROG_TYPE_KPROBE, -1, 0, NULL);
> + ASSERT_EQ(ret, 0, "invalid kfunc id:-1");
> +
> + /* invalid prog type */
> + ret = libbpf_probe_bpf_kfunc(100000, kfunc_id, 0, NULL);
> + if (!ASSERT_LE(ret, 0, "invalid prog type:100000"))
> + goto cleanup;

nit no need for the goto

jirka

> +
> +cleanup:
> + btf__free(btf);
> +}
> --
> 2.43.0
>