diff --git a/kernel/sched_cpupri.h b/kernel/sched_cpupri.h
index 0b6a3d1..6b38355 100644
--- a/kernel/sched_cpupri.h
+++ b/kernel/sched_cpupri.h
@@ -4,7 +4,7 @@
 #include <linux/sched.h>
 
 #define CPUPRI_NR_PRIORITIES 2+MAX_RT_PRIO
-#define CPUPRI_NR_PRI_WORDS CPUPRI_NR_PRIORITIES/BITS_PER_LONG
+#define CPUPRI_NR_PRI_WORDS (CPUPRI_NR_PRIORITIES + BITS_PER_LONG/2)/BITS_PER_LONG
 
 #define CPUPRI_INVALID -1
 #define CPUPRI_IDLE     0