The target_btf_id can help us understand which kernel function is
linked by a tracing prog. The target_btf_id and target_obj_id have
already been exposed to userspace, so we just need to show them.
The result as follows,
$ cat /proc/10673/fdinfo/10
pos: 0
flags: 02000000
mnt_id: 15
ino: 2094
link_type: tracing
link_id: 2
prog_tag: a04f5eef06a7f555
prog_id: 13
attach_type: 24
target_obj_id: 1
target_btf_id: 13964
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
Acked-by: Song Liu <song@xxxxxxxxxx>
---
kernel/bpf/syscall.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 909c112..870395a 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2968,10 +2968,18 @@ static void bpf_tracing_link_show_fdinfo(const struct bpf_link *link,
{
struct bpf_tracing_link *tr_link =
container_of(link, struct bpf_tracing_link, link.link);
+ u32 target_btf_id;
+ u32 target_obj_id;
+ bpf_trampoline_unpack_key(tr_link->trampoline->key,
+ &target_obj_id, &target_btf_id);
seq_printf(seq,
- "attach_type:\t%d\n",
- tr_link->attach_type);
+ "attach_type:\t%d\n"
+ "target_obj_id:\t%u\n"
+ "target_btf_id:\t%u\n",
+ tr_link->attach_type,
+ target_obj_id,
+ target_btf_id);
}
static int bpf_tracing_link_fill_link_info(const struct bpf_link *link,
--
1.8.3.1
