Nucleus

diff --git a/object/manager.c b/object/manager.c
index a274408..7e6da04 100644
--- a/object/manager.c
+++ b/object/manager.c
@@ -6,14 +6,22 @@
  * controls their instantiation and deletion.
  */
 
-#include <nucleus/object.h>
+#include <nucleus/kernel.h>
 #include <nucleus/memory.h>
-#include <nucleus/panic.h>
+#include <nucleus/object.h>
 
 void init_lock(Spinlock *lock);
 void acquire(Spinlock *lock);
 void release(Spinlock *lock);
 
+/* Check the magic of an object */
+int
+check(void *addr)
+{
+	Object *obj = addr;
+	return (obj && obj->magic == OBJECT_MAGIC);
+}
+
 /* Obtain a reference to an object */
 void *
 get(void *addr)
@@ -37,6 +45,7 @@ put(void *addr)
 	if (obj->type->delete)
 		obj->type->delete(obj);
 	remove(obj->type->objects, obj);
+	obj->magic = 0;
 	if (obj->type->free)
 		obj->type->free(obj);
 	else