--- a/src/racket/gc2/newgc.c	
+++ a/src/racket/gc2/newgc.c	
@@ -3895,7 +3895,7 @@ void GC_dump_variable_stack(void **var_stack,
   stack_get_type_name = get_type_name;
   stack_get_xtagged_name = get_xtagged_name;
   stack_print_tagged_value = print_tagged_value;
-  GC_do_dump_variable_stack(var_stack, delta, limit, stack_mem);
+  GC_do_dump_variable_stack(var_stack, delta, limit, stack_mem, GC_get_GC());
 }
 
 #endif