On Tue, May 16, 2023 at 5:39 AM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
>
> 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;
nit: combine on a single line?
>
> + bpf_trampoline_unpack_key(tr_link->trampoline->key,
> + &target_obj_id, &target_btf_id);
formatting seems odd?...
> 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
>
