Determine if symbols are sorted, set the sorted flag and sort under
the dso lock. Done in the interest of thread safety.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/map.c    | 3 +--
 tools/perf/util/symbol.c | 8 ++++++--
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index f30d34903aa4..a45708289cc6 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -398,8 +398,7 @@ struct symbol *map__find_symbol_by_name(struct map *map, const char *name)
 		return NULL;
 
 	dso = map__dso(map);
-	if (!dso__sorted_by_name(dso))
-		dso__sort_by_name(dso);
+	dso__sort_by_name(dso);
 
 	return dso__find_symbol_by_name(dso, name);
 }
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index d275d3bef7d5..bb02047e1c59 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -613,8 +613,12 @@ struct symbol *dso__find_symbol_by_name(struct dso *dso, const char *name)
 
 void dso__sort_by_name(struct dso *dso)
 {
-	dso__set_sorted_by_name(dso);
-	return symbols__sort_by_name(&dso->symbol_names, &dso->symbols);
+	mutex_lock(&dso->lock);
+	if (!dso__sorted_by_name(dso)) {
+		symbols__sort_by_name(&dso->symbol_names, &dso->symbols);
+		dso__set_sorted_by_name(dso);
+	}
+	mutex_unlock(&dso->lock);
 }
 
 /*
-- 
2.41.0.162.gfafddb0af9-goog