Index: kernel/generic/include/ipc/kbox.h
===================================================================
--- kernel/generic/include/ipc/kbox.h	(revision 2c57ee144b471022bccca5f06ef68134ccc17208)
+++ kernel/generic/include/ipc/kbox.h	(revision c3c56403688503c6117d80196b0ec43bfff388d4)
@@ -38,4 +38,16 @@
 #include <typedefs.h>
 
+/** Kernel answerbox structure. */
+typedef struct kbox {
+	/** The answerbox itself. */
+	answerbox_t box;
+	/** Thread used to service the answerbox. */
+	struct thread *thread;
+	/** Kbox thread creation vs. begin of cleanup mutual exclusion. */
+	mutex_t cleanup_lock;
+	/** True if cleanup of kbox has already started. */
+	bool finished;
+} kbox_t;
+
 extern int ipc_connect_kbox(task_id_t);
 extern void ipc_kbox_cleanup(void);