On Sun, Jun 15, 2025 at 11:05:14PM +0800, Tao Chen wrote:
> Show kprobe_multi link info with fdinfo, the info as follows:
>
> link_type: kprobe_multi
> link_id: 3
> prog_tag: e8225cbcc9cdffef
> prog_id: 29
> type: kprobe_multi
> kprobe_cnt: 8
> missed: 0
> func: bpf_fentry_test1+0x0/0x20
> cookie: 1
> func: bpf_fentry_test2+0x0/0x20
> cookie: 7
> func: bpf_fentry_test3+0x0/0x20
> cookie: 2
> func: bpf_fentry_test4+0x0/0x20
> cookie: 3
> func: bpf_fentry_test5+0x0/0x20
> cookie: 4
> func: bpf_fentry_test6+0x0/0x20
> cookie: 5
> func: bpf_fentry_test7+0x0/0x20
> cookie: 6
> func: bpf_fentry_test8+0x0/0x10
> cookie: 8
>
> Signed-off-by: Tao Chen <chen.dylane@xxxxxxxxx>
> ---
> kernel/trace/bpf_trace.c | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 9a8ca8a8e2b..d060c61e4e4 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -2623,10 +2623,43 @@ static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link,
> return err;
> }
>
> +#ifdef CONFIG_PROC_FS
> +static void bpf_kprobe_multi_show_fdinfo(const struct bpf_link *link,
> + struct seq_file *seq)
> +{
> + struct bpf_kprobe_multi_link *kmulti_link;
> + char sym[KSYM_NAME_LEN];
> +
> + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);
> +
> + seq_printf(seq,
> + "type:\t%s\n"
> + "kprobe_cnt:\t%u\n"
> + "missed:\t%lu\n",
> + kmulti_link->flags == BPF_F_KPROBE_MULTI_RETURN ? "kretprobe_multi" :
> + "kprobe_multi",
> + kmulti_link->cnt,
> + kmulti_link->fp.nmissed);
> +
> + for (int i = 0; i < kmulti_link->cnt; i++) {
> + sprint_symbol(sym, kmulti_link->addrs[i]);
I think you could use specifier to do the translation for you,
check Documentation/core-api/printk-formats.rst:
%pS versatile_init+0x0/0x110 [module_name]
> + seq_printf(seq,
> + "func:\t%s\n"
> + "cookie:\t%llu\n",
> + sym,
> + kmulti_link->cookies[i]
> + );
bracket should be on the previous line
jirka
> + }
> +}
> +#endif
> +
> static const struct bpf_link_ops bpf_kprobe_multi_link_lops = {
> .release = bpf_kprobe_multi_link_release,
> .dealloc_deferred = bpf_kprobe_multi_link_dealloc,
> .fill_link_info = bpf_kprobe_multi_link_fill_link_info,
> +#ifdef CONFIG_PROC_FS
> + .show_fdinfo = bpf_kprobe_multi_show_fdinfo,
> +#endif
> };
>
> static void bpf_kprobe_multi_cookie_swap(void *a, void *b, int size, const void *priv)
> --
> 2.48.1
>
