diff --git a/sys/kern/kern_timeout.c b/sys/kern/kern_timeout.c
--- a/sys/kern/kern_timeout.c
+++ b/sys/kern/kern_timeout.c
@@ -906,6 +906,8 @@
 			to_sbt = sbinuptime();
 		if ((flags & C_HARDCLOCK) == 0)
 			to_sbt += tick_sbt;
+		/* make sure the target time is really aligned to "tick_sbt" */
+		to_sbt -= to_sbt % tick_sbt;
 	} else
 		to_sbt = sbinuptime();
 	if (SBT_MAX - to_sbt < sbt)