diff --git a/lib/util.ts b/lib/util.ts
index f3bafa9d2..e43bb1ed2 100644
--- a/lib/util.ts
+++ b/lib/util.ts
@@ -53,7 +53,7 @@ export function runFilenameOrFn_(
           err = new Error(err);
         } else {
           err = err as Error;
-          if (err.stack) {
+          if (!err.stack) {
             err.stack = new Error().stack;
           }
         }