在 2025/6/24 06:14, Andrii Nakryiko 写道:

On Mon, Jun 23, 2025 at 6:45 AM Tao Chen [off-list ref] wrote:

quoted

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 <redacted>
---
  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...

will fix it in v6, thanks.

quoted

+                  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

-- 
Best Regards
Tao Chen