linux-kernel - [PATCH] tracing/kprobes: 'nmissed' not showed correctly for kretprobe

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Date:   Sat, 11 Dec 2021 23:00:32 +0800
From:   Xiangyang Zhang <xyz.sun.ok@...il.com>
To:     rostedt@...dmis.org, mingo@...hat.com
Cc:     masami.hiramatsu.pt@...achi.com, oleg@...hat.com,
        namhyung.kim@....com, linux-kernel@...r.kernel.org,
        xyz.sun.ok@...il.com
Subject: [PATCH] tracing/kprobes: 'nmissed' not showed correctly for kretprobe

The 'nmissed' column of the 'kprobe_profile' file for kretprobe is
always zero, because 'nmissed' for kretprobe is maintained in
'tk->rp.nmissed' but not in 'tk->rp.kp.nmissed'

Fixes: c31ffb3ff633 ("tracing/kprobes: Factor out struct trace_probe")
Signed-off-by: Xiangyang Zhang <xyz.sun.ok@...il.com>
---
 kernel/trace/trace_kprobe.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index d10c01948e68..2b9de6826e94 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1175,15 +1175,17 @@ static int probes_profile_seq_show(struct seq_file *m, void *v)
 {
 	struct dyn_event *ev = v;
 	struct trace_kprobe *tk;
+	unsigned long nmissed = 0;
 
 	if (!is_trace_kprobe(ev))
 		return 0;
 
 	tk = to_trace_kprobe(ev);
+	nmissed = tk->rp.handler ? tk->rp.nmissed : tk->rp.kp.nmissed;
 	seq_printf(m, "  %-44s %15lu %15lu\n",
 		   trace_probe_name(&tk->tp),
 		   trace_kprobe_nhit(tk),
-		   tk->rp.kp.nmissed);
+		   nmissed);
 
 	return 0;
 }
-- 
2.25.1