From: Xiangyang Zhang <xyz.sun.ok@gmail.com>

Date: Fri, 7 Jan 2022 23:02:42 +0800

Subject: tracing/kprobes: 'nmissed' not showed correctly for kretprobe

Git-commit: dfea08a2116fe327f79d8f4d4b2cf6e0c88be11f

Patch-mainline: v5.16 or v5.16-rc9 (next release)

References: git-fixes

The 'nmissed' column of the 'kprobe_profile' file for kretprobe is

not showed correctly, kretprobe can be skipped by two reasons,

shortage of kretprobe_instance which is counted by tk->rp.nmissed,

and kprobe itself is missed by some reason, so to show the sum.

Link: https://lkml.kernel.org/r/20220107150242.5019-1-xyz.sun.ok@gmail.com

Cc: stable@vger.kernel.org

Fixes: 4a846b443b4e ("tracing/kprobes: Cleanup kprobe tracer code")

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Signed-off-by: Xiangyang Zhang <xyz.sun.ok@gmail.com>

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Acked-by: Miroslav Benes <mbenes@suse.cz>

---

 kernel/trace/trace_kprobe.c | 5 ++++-

 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c

index f8c26ee72de3..3d85323278ed 100644

--- a/kernel/trace/trace_kprobe.c

+++ b/kernel/trace/trace_kprobe.c

@@ -1170,15 +1170,18 @@ static int probes_profile_seq_show(struct seq_file *m, void *v)

 {

 	struct dyn_event *ev = v;

 	struct trace_kprobe *tk;

+	unsigned long nmissed;

 	if (!is_trace_kprobe(ev))

 		return 0;

 	tk = to_trace_kprobe(ev);

+	nmissed = trace_kprobe_is_return(tk) ?

+		tk->rp.kp.nmissed + 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;

 }