diff --git a/common/modules/buffer.jsm b/common/modules/buffer.jsm
index 4c81da9b..fa854289 100644
--- a/common/modules/buffer.jsm
+++ b/common/modules/buffer.jsm
@@ -548,7 +548,7 @@ var Buffer = Module("Buffer", {
                             yield res[i];
         }
 
-        for (let frame of this.allFrames(null, true))
+        for (let frame of this.allFrames(undefined, true))
             for (let elem of followFrame(frame))
                 if (count-- === 0) {
                     if (follow)