perf probe: Do not show the skipped events

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>

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 70548df2abb92f797721684e9a687a5b0fdacbf3..6b1507566770140da4519887bec6543eabe404b1 100644 (file)
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -364,6 +364,9 @@ static int perf_add_probe_events(struct perf_probe_event *pevs, int npevs)
 
                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,