diff --git a/scheme/vm/gc-root.scm b/scheme/vm/gc-root.scm
index 591fc06..8e16463 100644
--- a/scheme/vm/gc-root.scm
+++ b/scheme/vm/gc-root.scm
@@ -68,6 +68,7 @@
   (let ((okay? (address= *external-root-stack*
 			 *external-root-stack-base*)))
     (set! *external-root-stack-base* old-base)
+    (set! *external-root-stack* old-base)
     okay?))
 
 ;----------------