diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
index c6a06b71594d..f40578026a04 100644
--- a/Documentation/accounting/getdelays.c
+++ b/Documentation/accounting/getdelays.c
@@ -314,6 +314,7 @@ int main(int argc, char *argv[])
 			break;
 		case 'm':
 			strncpy(cpumask, optarg, sizeof(cpumask));
+			cpumask[sizeof(cpumask) - 1] = '\0';
 			maskset = 1;
 			printf("cpumask %s maskset %d\n", cpumask, maskset);
 			break;