diff --git a/gc.c b/gc.c
index 247e4bfd85..49b5cbce5e 100644
--- a/gc.c
+++ b/gc.c
@@ -6231,7 +6231,7 @@ rb_gc_force_recycle(VALUE obj)
 void
 rb_gc_register_mark_object(VALUE obj)
 {
-    VALUE ary_ary = GET_THREAD()->vm->mark_object_ary;
+    VALUE ary_ary = GET_VM()->mark_object_ary;
     VALUE ary = rb_ary_last(0, 0, ary_ary);
 
     if (ary == Qnil || RARRAY_LEN(ary) >= MARK_OBJECT_ARY_BUCKET_SIZE) {