diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 6c7dcc1..7ff3c8f 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -319,7 +319,8 @@
 		break;
 
 	default:
-		scnprintf(bf, sizeof(bf), "%s", "unknown attr type");
+		scnprintf(bf, sizeof(bf), "unknown attr type: %d",
+			  evsel->attr.type);
 		break;
 	}