On Mon, Jun 23, 2025 at 6:45 AM Tao Chen <chen.dylane@xxxxxxxxx> wrote:
>
> Show uprobe_multi link info with fdinfo, the info as follows:
>
> link_type: uprobe_multi
> link_id: 10
> prog_tag: 7db356c03e61a4d4
> prog_id: 42
> uprobe_cnt: 3
> pid: 0
> path: /home/dylane/bpf/tools/testing/selftests/bpf/test_progs
> offset ref_ctr_offset cookie
> 0xa69f13 0x0 2
> 0xa69f1e 0x0 3
> 0xa69f29 0x0 1
>
> Signed-off-by: Tao Chen <chen.dylane@xxxxxxxxx>
> ---
> kernel/trace/bpf_trace.c | 44 ++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 44 insertions(+)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 8ecb1a9f85d..90209dda819 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -3171,10 +3171,54 @@ static int bpf_uprobe_multi_link_fill_link_info(const struct bpf_link *link,
> return err;
> }
>
> +#ifdef CONFIG_PROC_FS
> +static void bpf_uprobe_multi_show_fdinfo(const struct bpf_link *link,
> + struct seq_file *seq)
> +{
> + struct bpf_uprobe_multi_link *umulti_link;
> + char *p, *buf;
> +
> + umulti_link = container_of(link, struct bpf_uprobe_multi_link, link);
> +
> + buf = kmalloc(PATH_MAX, GFP_KERNEL);
> + if (!buf)
> + return;
> +
> + p = d_path(&umulti_link->path, buf, PATH_MAX);
> + if (IS_ERR(p)) {
> + kfree(buf);
> + return;
> + }
> +
> + seq_printf(seq,
> + "uprobe_cnt:\t%u\n"
> + "pid:\t%u\n"
> + "path:\t%s\n",
> + umulti_link->cnt,
> + umulti_link->task ? task_pid_nr_ns(umulti_link->task,
> + task_active_pid_ns(current)) : 0,
nit: either keep stuff like this on single line, or if it's too long
or awkward, add a local variable. Formatting it like this is very hard
to follow and looks pretty ugly...
> + p);
> +
> + seq_printf(seq, "%-16s %-16s %-16s\n", "offset", "ref_ctr_offset", "cookie");
> + for (int i = 0; i < umulti_link->cnt; i++) {
> + seq_printf(seq,
> + "%#-16llx %#-16lx %-16llu\n",
> + umulti_link->uprobes[i].offset,
> + umulti_link->uprobes[i].ref_ctr_offset,
> + umulti_link->uprobes[i].cookie);
> + }
> +
> + kfree(buf);
> +}
> +#endif
> +
> static const struct bpf_link_ops bpf_uprobe_multi_link_lops = {
> .release = bpf_uprobe_multi_link_release,
> .dealloc_deferred = bpf_uprobe_multi_link_dealloc,
> .fill_link_info = bpf_uprobe_multi_link_fill_link_info,
> +#ifdef CONFIG_PROC_FS
> + .show_fdinfo = bpf_uprobe_multi_show_fdinfo,
> +#endif
> };
>
> static int uprobe_prog_run(struct bpf_uprobe *uprobe,
> --
> 2.48.1
>
