Index: kernel/generic/src/proc/thread.c
===================================================================
--- kernel/generic/src/proc/thread.c	(revision 4acaa7c0d4fdaf4f08ad44578e5a437a7f8dc98f)
+++ kernel/generic/src/proc/thread.c	(revision f8d07859b6017d3d1d14299d1d1d20ec6b269e69)
@@ -454,4 +454,10 @@
 		/* Generate udebug THREAD_E event */
 		udebug_thread_e_event();
+
+		/*
+		 * This thread will not execute any code or system calls from
+		 * now on.
+		 */
+		udebug_stoppable_begin();
 #endif
 		if (atomic_predec(&TASK->lifecount) == 0) {