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

Tao Chen
2025-01-24T14:44:56Z

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