On Fri, Jun 6, 2025 at 8:03 AM Tao Chen <chen.dylane@xxxxxxxxx> wrote:
>
> After commit 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") add
> perf_event info, we can also show the info with the method of cat /proc/[fd]/fdinfo.
>
> kprobe fdinfo:
> link_type: perf
> link_id: 10
> prog_tag: bcf7977d3b93787c
> prog_id: 20
> name: bpf_fentry_test1
> offset: 0
> missed: 0
> addr: ffffffffa28a2904
> event_type: kprobe
> cookie: 3735928559
>
> uprobe fdinfo:
> link_type: perf
> link_id: 13
> prog_tag: bcf7977d3b93787c
> prog_id: 21
> name: /proc/self/exe
> offset: 63dce4
> ref_ctr_offset: 33eee2a
> event_type: uprobe
> cookie: 3735928559
>
> tracepoint fdinfo:
> link_type: perf
> link_id: 11
> prog_tag: bcf7977d3b93787c
> prog_id: 22
> tp_name: sched_switch
> event_type: tracepoint
> cookie: 3735928559
>
> perf_event fdinfo:
> link_type: perf
> link_id: 12
> prog_tag: bcf7977d3b93787c
> prog_id: 23
> type: 1
> config: 2
> event_type: event
> cookie: 3735928559
>
> Signed-off-by: Tao Chen <chen.dylane@xxxxxxxxx>
> ---
> kernel/bpf/syscall.c | 118 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 118 insertions(+)
>
> Change list:
> - v1 -> v2:
> - Andrii suggested:
> 1. define event_type with string
> 2. print offset and addr with hex
>
> - Jiri suggested:
> 1. add ref_ctr_offset for uprobe
> - v1:
> https://lore.kernel.org/bpf/20250604163723.3175258-1-chen.dylane@xxxxxxxxx
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 89d027cd7ca..928ff129087 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -3795,6 +3795,31 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
> info->perf_event.kprobe.cookie = event->bpf_cookie;
> return 0;
> }
> +
> +static void bpf_perf_link_fdinfo_kprobe(const struct perf_event *event,
> + struct seq_file *seq)
> +{
> + const char *name;
> + int err;
> + u32 prog_id, type;
> + u64 offset, addr;
> + unsigned long missed;
> +
> + err = bpf_get_perf_event_info(event, &prog_id, &type, &name,
> + &offset, &addr, &missed);
> + if (err)
> + return;
> +
> + seq_printf(seq,
> + "name:\t%s\n"
> + "offset:\t%llx\n"
I used %#llx to have 0x prepended in front of hex values (here and in
a few other places). That seems to be what we do in other fdinfo
handlers. Applied to bpf-next, thanks.
> + "missed:\t%lu\n"
> + "addr:\t%llx\n"
> + "event_type:\t%s\n"
> + "cookie:\t%llu\n",
> + name, offset, missed, addr, type == BPF_FD_TYPE_KRETPROBE ?
> + "kretprobe" : "kprobe", event->bpf_cookie);
> +}
> #endif
>
> #ifdef CONFIG_UPROBE_EVENTS
[...]
