Index: libcfa/src/concurrency/kernel/startup.cfa
===================================================================
--- libcfa/src/concurrency/kernel/startup.cfa	(revision 0240cd69344ae60a0769209865608407d23aa144)
+++ libcfa/src/concurrency/kernel/startup.cfa	(revision 62502cc441e4799ba5cc3321cae2659b02cab74b)
@@ -516,5 +516,8 @@
 	( this.terminated ){ 0 };
 	( this.runner ){};
-	init( this, name, _cltr );
+
+	disable_interrupts();
+		init( this, name, _cltr );
+	enable_interrupts( __cfaabi_dbg_ctx );
 
 	__cfadbg_print_safe(runtime_core, "Kernel : Starting core %p\n", &this);
@@ -540,5 +543,7 @@
 	free( this.stack );
 
-	deinit( this );
+	disable_interrupts();
+		deinit( this );
+	enable_interrupts( __cfaabi_dbg_ctx );
 }
 
Index: libcfa/src/concurrency/ready_queue.cfa
===================================================================
--- libcfa/src/concurrency/ready_queue.cfa	(revision 0240cd69344ae60a0769209865608407d23aa144)
+++ libcfa/src/concurrency/ready_queue.cfa	(revision 62502cc441e4799ba5cc3321cae2659b02cab74b)
@@ -150,4 +150,6 @@
 //  queues or removing them.
 uint_fast32_t ready_mutate_lock( void ) with(*__scheduler_lock) {
+	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
+
 	// Step 1 : lock global lock
 	// It is needed to avoid processors that register mid Critical-Section
@@ -164,8 +166,11 @@
 	}
 
+	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
 	return s;
 }
 
 void ready_mutate_unlock( uint_fast32_t last_s ) with(*__scheduler_lock) {
+	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
+
 	// Step 1 : release local locks
 	// This must be done while the global lock is held to avoid
@@ -182,4 +187,6 @@
 	/*paranoid*/ assert(true == lock);
 	__atomic_store_n(&lock, (bool)false, __ATOMIC_RELEASE);
+
+	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
 }