--- a/sys/netgraph7/ng_pred1.c
+++ b/sys/netgraph7/ng_pred1.c
@@ -397 +397 @@
-	if (inlen > (PRED1_BUF_SIZE*8/9 + 1 + 4)) {
+	if (inlen > PRED1_BUF_SIZE - 2 - ((PRED1_BUF_SIZE - 2) / 9 + 1)) {
 		/* 4094 - 455 = 3639: worst-case n + ceil(n/8) fits in 4094 */