Index: src/gc/smallobject.c
===================================================================
--- src/gc/smallobject.c	(revision 35302)
+++ src/gc/smallobject.c	(working copy)
@@ -277,6 +277,7 @@
 
     ptr             = free_list;
     pool->free_list = PMC_struct_val(ptr);
+    PMC_struct_val(ptr) = NULL;
 
     PObj_flags_SETTO(ptr, 0);