diff --git a/lib/stack.js b/lib/stack.js
index c8d37b51a..a066f3d47 100644
--- a/lib/stack.js
+++ b/lib/stack.js
@@ -173,7 +173,7 @@ var re = new RegExp(
 )
 
 function parseLine (line) {
-  var match = line.match(re)
+  var match = line && line.match(re)
   if (!match)
     return null