diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 3cadc252dd8977f4117419db240ac87183e54bea..ac3c59e7da1654292c9d1c13525ad84a166b6160 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -3521,7 +3521,7 @@ perf_event__synthesize_event_update_unit(struct perf_tool *tool,
 	if (ev == NULL)
 		return -ENOMEM;
 
-	strncpy(ev->data, evsel->unit, size);
+	strlcpy(ev->data, evsel->unit, size + 1);
 	err = process(tool, (union perf_event *)ev, NULL, NULL);
 	free(ev);
 	return err;