diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 5cd41ec..c2c9734 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -245,8 +245,11 @@
 {
 	struct hist_entry *he;
 
+	pthread_mutex_lock(&evsel->hists.lock);
 	he = __hists__add_entry(&evsel->hists, al, NULL, sample->period,
 				sample->weight);
+	pthread_mutex_unlock(&evsel->hists.lock);
+
 	if (he == NULL)
 		return NULL;