diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index ea55c7a..5870efb 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -270,7 +270,7 @@
 	long sec = tp->tv_sec;
 	long nsec = tp->tv_nsec + res - 1;
 
-	if (nsec > NSEC_PER_SEC) {
+	if (nsec >= NSEC_PER_SEC) {
 		sec++;
 		nsec -= NSEC_PER_SEC;
 	}
@@ -1209,13 +1209,9 @@
 
 	do_posix_clock_monotonic_gettime_parts(tp, &wall_to_mono);
 
-	tp->tv_sec += wall_to_mono.tv_sec;
-	tp->tv_nsec += wall_to_mono.tv_nsec;
+	set_normalized_timespec(tp, tp->tv_sec + wall_to_mono.tv_sec,
+				tp->tv_nsec + wall_to_mono.tv_nsec);
 
-	if ((tp->tv_nsec - NSEC_PER_SEC) > 0) {
-		tp->tv_nsec -= NSEC_PER_SEC;
-		tp->tv_sec++;
-	}
 	return 0;
 }