diff --git a/src/vnet/interface/runtime.c b/src/vnet/interface/runtime.c
index c1b096f..f4c09be 100644
--- a/src/vnet/interface/runtime.c
+++ b/src/vnet/interface/runtime.c
@@ -193,6 +193,7 @@
 		{
 		  clib_interrupt_clear (in, int_num);
 		  pending_int = clib_bitmap_set (pending_int, int_num, 1);
+		  last_int = clib_max (last_int, int_num);
 		}
 	    }