Re: [PATCH bpf-next v8 4/4] selftests/bpf: Add libbpf_probe_bpf_kfunc API selftests

Eduard Zingerman
2025-02-21T18:19:59Z

On Sat, 2025-02-22 at 00:33 +0800, Tao Chen wrote:

[...]

> +static const struct {
> + const char *name;
> + int code;
> +} program_types[] = {
> +#define _T(n) { #n, BPF_PROG_TYPE_##n }
> + _T(KPROBE),
> + _T(XDP),
> + _T(SYSCALL),
> + _T(SCHED_CLS),
> + _T(SCHED_ACT),
> + _T(SK_SKB),
> + _T(SOCKET_FILTER),
> + _T(CGROUP_SKB),
> + _T(LWT_OUT),
> + _T(LWT_IN),
> + _T(LWT_XMIT),
> + _T(LWT_SEG6LOCAL),
> + _T(NETFILTER),
> + _T(CGROUP_SOCK_ADDR),
> + _T(SCHED_ACT)
> +#undef _T
> +};
> +
> +void test_libbpf_probe_kfuncs_many(void)
> +{

Hi Tao,

Sorry, probably some miscommunication from my side.
I did not mean this test for inclusion, it was meant as a one time
manual inspection of libbpf_probe_bpf_kfunc results.
Just as a sanity check before series is merged.
As an automated test it does not provide much meaningful signal.

> + int i, kfunc_id, ret, id;
> + const struct btf_type *t;
> + struct btf *btf = NULL;
> + const char *kfunc;
> + const char *tag;
> +
> + btf = btf__parse("/sys/kernel/btf/vmlinux", NULL);
> + if (!ASSERT_OK_PTR(btf, "btf_parse"))
> + return;
> + for (id = 0; id < btf__type_cnt(btf); ++id) {
> + t = btf__type_by_id(btf, id);
> + if (!t)
> + continue;
> + if (!btf_is_decl_tag(t))
> + continue;
> + tag = btf__name_by_offset(btf, t->name_off);
> + if (strcmp(tag, "bpf_kfunc") != 0)
> + continue;
> + kfunc_id = t->type;
> + t = btf__type_by_id(btf, kfunc_id);
> + if (!btf_is_func(t))
> + continue;
> + kfunc = btf__name_by_offset(btf, t->name_off);
> + for (i = 0; i < ARRAY_SIZE(program_types); ++i) {
> + ret = libbpf_probe_bpf_kfunc(program_types[i].code,
> + kfunc_id, -1, NULL);
> + if (ret < 0) {
> + ASSERT_FAIL("kfunc:%s use prog type:%d",
> + kfunc, program_types[i].code);
> + goto cleanup;
> + }
> + }
> + }
> +cleanup:
> + btf__free(btf);
> +}