diff --git a/ext/objspace/object_tracing.c b/ext/objspace/object_tracing.c
index a057ac2a96..a122247e3b 100644
--- a/ext/objspace/object_tracing.c
+++ b/ext/objspace/object_tracing.c
@@ -110,6 +110,7 @@ newobj_i(VALUE tpval, void *data)
     info->class_path = class_path_cstr;
     info->generation = rb_gc_count();
     st_insert(arg->object_table, (st_data_t)obj, (st_data_t)info);
+    RB_GC_GUARD(obj);
 }
 
 static void