diff --git a/gc/default/default.c b/gc/default/default.c
index 124c5de3eb..038a330e9e 100644
--- a/gc/default/default.c
+++ b/gc/default/default.c
@@ -6191,7 +6191,7 @@ rb_gc_impl_writebarrier_remember(void *objspace_ptr, VALUE obj)
     }
 }
 
-#define RB_GC_OBJECT_METADATA_ENTRY_COUNT 7
+#define RB_GC_OBJECT_METADATA_ENTRY_COUNT 9
 static struct rb_gc_object_metadata_entry object_metadata_entries[RB_GC_OBJECT_METADATA_ENTRY_COUNT + 1];
 
 struct rb_gc_object_metadata_entry *