diff --git a/sys/kern/kern_nrandom.c b/sys/kern/kern_nrandom.c
--- a/sys/kern/kern_nrandom.c
+++ b/sys/kern/kern_nrandom.c
@@ -662,7 +662,7 @@
 			if (n > 256)
 				n = 256;
 		}
-		add_buffer_randomness_state(state, buf, bytes, srcid);
+		add_buffer_randomness_state(state, buf, n, srcid);
 		bytes -= n;
 		buf += n;
 	}