perf parse: Report initial event parsing error

Record the first event parsing error and report. Implementing feedback
from Jiri Olsa:

  https://lkml.org/lkml/2019/10/28/680

An example error is:

  $ tools/perf/perf stat -e c/c/
  WARNING: multiple event parsing errors
  event syntax error: 'c/c/'
                         \___ unknown term

  valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore

Initial error:

  event syntax error: 'c/c/'
                      \___ Cannot find PMU `c'. Missing kernel support?
  Run 'perf list' for a list of valid events

   Usage: perf stat [<options>] [<command>]

      -e, --event <event>   event selector. use 'perf list' to list available events

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: http://lore.kernel.org/lkml/20191116074652.9960-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 43c05eae1768..46a72ecac427 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -3016,11 +3016,18 @@ static bool evlist__add_vfs_getname(struct evlist *evlist)
 {
 	bool found = false;
 	struct evsel *evsel, *tmp;
-	struct parse_events_error err = { .idx = 0, };
-	int ret = parse_events(evlist, "probe:vfs_getname*", &err);
+	struct parse_events_error err;
+	int ret;
 
-	if (ret)
+	bzero(&err, sizeof(err));
+	ret = parse_events(evlist, "probe:vfs_getname*", &err);
+	if (ret) {
+		free(err.str);
+		free(err.help);
+		free(err.first_str);
+		free(err.first_help);
 		return false;
+	}
 
 	evlist__for_each_entry_safe(evlist, evsel, tmp) {
 		if (!strstarts(perf_evsel__name(evsel), "probe:vfs_getname"))
@@ -4832,8 +4839,9 @@ int cmd_trace(int argc, const char **argv)
 	 * wrong in more detail.
 	 */
 	if (trace.perfconfig_events != NULL) {
-		struct parse_events_error parse_err = { .idx = 0, };
+		struct parse_events_error parse_err;
 
+		bzero(&parse_err, sizeof(parse_err));
 		err = parse_events(trace.evlist, trace.perfconfig_events, &parse_err);
 		if (err) {
 			parse_events_print_error(&parse_err, trace.perfconfig_events);