diff --git a/gc.c b/gc.c
index 1ec159a2da..68304d26c5 100644
--- a/gc.c
+++ b/gc.c
@@ -1618,6 +1618,12 @@ os_each_obj(int argc, VALUE *argv, VALUE os)
 
 static VALUE
 undefine_final(VALUE os, VALUE obj)
+{
+    return rb_undefine_finalizer(obj);
+}
+
+VALUE
+rb_undefine_finalizer(VALUE obj)
 {
     rb_check_frozen(obj);