diff --git a/sys/kern/subr_rtc.c b/sys/kern/subr_rtc.c
index dbad36dbec8..4bac3247c25 100644
--- a/sys/kern/subr_rtc.c
+++ b/sys/kern/subr_rtc.c
@@ -172,11 +172,11 @@ resettodr(void)
 	if (disable_rtc_set || clock_dev == NULL)
 		return;
 
-	mtx_lock(&resettodr_lock);
 	getnanotime(&ts);
 	timespecadd(&ts, &clock_adj);
 	ts.tv_sec -= utc_offset();
 	/* XXX: We should really set all registered RTCs */
+	mtx_lock(&resettodr_lock);
 	error = CLOCK_SETTIME(clock_dev, &ts);
 	mtx_unlock(&resettodr_lock);
 	if (error != 0)