selftests/bpf: Add link info test for ref_ctr_offset retrieval

Adding link info test for ref_ctr_offset retrieval for both
uprobe and uretprobe probes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/bpf/20250509153539.779599-3-jolsa@kernel.org

diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
index e59af2a..e401146 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
+++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
@@ -37,6 +37,7 @@ static noinline void uprobe_func(void)
 static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long addr,
                                 ssize_t offset, ssize_t entry_offset)
 {
+       ssize_t ref_ctr_offset = entry_offset /* ref_ctr_offset for uprobes */;
        struct bpf_link_info info;
        __u32 len = sizeof(info);
        char buf[PATH_MAX];
@@ -97,6 +98,7 @@ again:
        case BPF_PERF_EVENT_UPROBE:
        case BPF_PERF_EVENT_URETPROBE:
                ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+               ASSERT_EQ(info.perf_event.uprobe.ref_ctr_offset, ref_ctr_offset, "uprobe_ref_ctr_offset");
 
                ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1,
                                  "name_len");
@@ -241,20 +243,32 @@ static void test_uprobe_fill_link_info(struct test_fill_link_info *skel,
                .retprobe = type == BPF_PERF_EVENT_URETPROBE,
                .bpf_cookie = PERF_EVENT_COOKIE,
        );
+       const char *sema[1] = {
+               "uprobe_link_info_sema_1",
+       };
+       __u64 *ref_ctr_offset;
        struct bpf_link *link;
        int link_fd, err;
 
+       err = elf_resolve_syms_offsets("/proc/self/exe", 1, sema,
+                                      (unsigned long **) &ref_ctr_offset, STT_OBJECT);
+       if (!ASSERT_OK(err, "elf_resolve_syms_offsets_object"))
+               return;
+
+       opts.ref_ctr_offset = *ref_ctr_offset;
        link = bpf_program__attach_uprobe_opts(skel->progs.uprobe_run,
                                               0, /* self pid */
                                               UPROBE_FILE, uprobe_offset,
                                               &opts);
        if (!ASSERT_OK_PTR(link, "attach_uprobe"))
-               return;
+               goto out;
 
        link_fd = bpf_link__fd(link);
-       err = verify_perf_link_info(link_fd, type, 0, uprobe_offset, 0);
+       err = verify_perf_link_info(link_fd, type, 0, uprobe_offset, *ref_ctr_offset);
        ASSERT_OK(err, "verify_perf_link_info");
        bpf_link__destroy(link);
+out:
+       free(ref_ctr_offset);
 }
 
 static int verify_kmulti_link_info(int fd, bool retprobe, bool has_cookies)