[PATCH 4.4 100/101] perf probe: Do not show the skipped events

Greg Kroah-Hartman
2020-06-19T16:49:26Z

From: Masami Hiramatsu <mhiramat@kernel.org>

commit f41ebe9defacddeae96a872a33f0f22ced0bfcef upstream.

When a probe point is expanded to several places (like inlined) and if
some of them are skipped because of blacklisted or __init function,
those trace_events has no event name. It must be skipped while showing
results.

Without this fix, you can see "(null):(null)" on the list,

# ./perf probe request_resource
reserve_setup is out of .text, skip it.
Added new events:
(null):(null) (on request_resource)
probe:request_resource (on request_resource)

You can now use it in all perf tools, such as:

perf record -e probe:request_resource -aR sleep 1

#

With this fix, it is ignored:

# ./perf probe request_resource
reserve_setup is out of .text, skip it.
Added new events:
probe:request_resource (on request_resource)

You can now use it in all perf tools, such as:

perf record -e probe:request_resource -aR sleep 1

#

Fixes: 5a51fcd1f30c ("perf probe: Skip kernel symbols which is out of .text")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/158763968263.30755.12800484151476026340.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
tools/perf/builtin-probe.c | 3 +++
1 file changed, 3 insertions(+)

--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -336,6 +336,9 @@ static int perf_add_probe_events(struct

for (k = 0; k < pev->ntevs; k++) {
struct probe_trace_event *tev = &pev->tevs[k];
+ /* Skipped events have no event name */
+ if (!tev->event)
+ continue;

/* We use tev's name for showing new events */
show_perf_probe_event(tev->group, tev->event, pev,