diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 419a52c..82b7c9e 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -923,7 +923,10 @@
 
 static int __init ntp_tick_adj_setup(char *str)
 {
-	ntp_tick_adj = simple_strtol(str, NULL, 0);
+	int rc = kstrtol(str, 0, (long *)&ntp_tick_adj);
+
+	if (rc)
+		return rc;
 	ntp_tick_adj <<= NTP_SCALE_SHIFT;
 
 	return 1;