Index: kernel/generic/src/ddi/irq.c
===================================================================
--- kernel/generic/src/ddi/irq.c	(revision 96b02eb9b2f96f3843b8275c254c43a9cb6c8c88)
+++ kernel/generic/src/ddi/irq.c	(revision c81b6f22157e856a3500cbdf031cc5acfd0348e6)
@@ -136,4 +136,7 @@
 static size_t buckets;
 
+/** Last valid INR. */
+inr_t last_inr = 0;
+
 /** Initialize IRQ subsystem.
  *
@@ -145,4 +148,6 @@
 {
 	buckets = chains;
+	last_inr = inrs - 1;
+
 	/*
 	 * Be smart about the choice of the hash table operations.