[PATCH 5.4 253/320] tracing/kprobes: nmissed not showed correctly for kretprobe

Greg Kroah-Hartman
2022-01-24T19:50:34Z

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

commit dfea08a2116fe327f79d8f4d4b2cf6e0c88be11f upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/trace/trace_kprobe.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -999,15 +999,18 @@ static int probes_profile_seq_show(struc
{
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;
}