perf trace: Free syscall tp fields in evsel->priv

ASan reports several memory leaks running:

  # perf test "88: Check open filename arg using perf trace + vfs_getname"

The third of these leaks is related to evsel->priv fields of sycalls
never being deallocated.

This patch adds the function evlist__free_syscall_tp_fields which
iterates over all evsels in evlist, matching syscalls, and calling the
missing frees.

This new function is called at the end of trace__run, right before
calling evlist__delete.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Cc: Ian Rogers <irogers@google.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>
Link: http://lore.kernel.org/lkml/46526611904ec5ff2768b59014e3afce8e0197d1.1626343282.git.rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -3103,6 +3103,21 @@ static struct evsel *evsel__new_pgfault(u64 config)
 	return evsel;
 }
 
+static void evlist__free_syscall_tp_fields(struct evlist *evlist)
+{
+	struct evsel *evsel;
+
+	evlist__for_each_entry(evlist, evsel) {
+		struct evsel_trace *et = evsel->priv;
+
+		if (!et || !evsel->tp_format || strcmp(evsel->tp_format->system, "syscalls"))
+			continue;
+
+		free(et->fmt);
+		free(et);
+	}
+}
+
 static void trace__handle_event(struct trace *trace, union perf_event *event, struct perf_sample *sample)
 {
 	const u32 type = event->header.type;
@@ -4138,7 +4153,7 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
 
 out_delete_evlist:
 	trace__symbols__exit(trace);
-
+	evlist__free_syscall_tp_fields(evlist);
 	evlist__delete(evlist);
 	cgroup__put(trace->cgroup);
 	trace->evlist = NULL;