bpf: Add tracing_multi link info support

Adding BPF_OBJ_GET_INFO_BY_FD support for tracing_multi links.

We expose following tracing_multi link data:
- attach_type of the program
- number of ids
- array of BTF ids
- array of its related kernel addresses
- array of cookies

The change follows the kprobe_multi and uprobe_multi link-info convention
of optional output arrays with an in/out count,

On top of standard tracing link data we also expose addresses, because they
are useful info for user (especially when the attachment was done via pattern).
This data is hidden when kallsyms does not allow exposing kernel pointer values.

Assisted-by: Codex:GPT-5

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Leon Hwang <leon.hwang@linux.dev>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260629212208.895962-2-jolsa@kernel.org

1 files changed, 9 insertions, 0 deletions

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c91b5a4bda03..2f1d24fef857 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6843,6 +6843,15 @@ struct bpf_link_info {
 			__u32 pid;
 		} uprobe_multi;
 		struct {
+			__u32 attach_type;
+			__u32 count; /* in/out: tracing_multi target count */
+			__u32 btf_obj_id;
+			__u32 :32;
+			__aligned_u64 ids;
+			__aligned_u64 addrs;
+			__aligned_u64 cookies;
+		} tracing_multi;
+		struct {
 			__u32 type; /* enum bpf_perf_event_type */
 			__u32 :32;
 			union {