Re: [PATCH bpf-next v6 3/3] bpf: Add show_fdinfo for kprobe_multi
From: Andrii Nakryiko <hidden>
Date: 2025-07-01 20:38:13
Also in:
bpf, lkml
On Fri, Jun 27, 2025 at 1:23 AM Tao Chen [off-list ref] wrote:
Show kprobe_multi link info with fdinfo, the info as follows: link_type: kprobe_multi link_id: 1 prog_tag: 33be53a4fd673e1d prog_id: 21 kprobe_cnt: 8 missed: 0 cookie func 1 bpf_fentry_test1+0x0/0x20 7 bpf_fentry_test2+0x0/0x20 2 bpf_fentry_test3+0x0/0x20 3 bpf_fentry_test4+0x0/0x20 4 bpf_fentry_test5+0x0/0x20 5 bpf_fentry_test6+0x0/0x20 6 bpf_fentry_test7+0x0/0x20 8 bpf_fentry_test8+0x0/0x10
two nits: 1) order of cookie. For uprobes you have cookie at the end, here in the front. Given variable-sized func name, I'd move cookie to the front for uprobes for consistency. 2) field sizing for cookie (16) is a) not sufficient for maximum possible u64 (20 digits) and b) very wasteful in common case of small numbers. So use tab instead of fixed-sized column? And why 16 character sizing for the func column? Just to have more spaces emitted? Other than that the series looks good to me. pw-bot: cr
quoted hunk ↗ jump to hunk
Signed-off-by: Tao Chen <redacted> --- kernel/trace/bpf_trace.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 1c75f9c6c66..e8f070504c4 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c@@ -2622,10 +2622,37 @@ 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; + + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link); + + seq_printf(seq, + "kprobe_cnt:\t%u\n" + "missed:\t%lu\n", + kmulti_link->cnt, + kmulti_link->fp.nmissed); + + seq_printf(seq, "%-16s %-16s\n", "cookie", "func"); + for (int i = 0; i < kmulti_link->cnt; i++) { + seq_printf(seq, + "%-16llu %-16pS\n", + kmulti_link->cookies[i], + (void *)kmulti_link->addrs[i]); + } +} +#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