diff --git a/net/ieee802154/dgram.c b/net/ieee802154/dgram.c
index 6fbb2ad7bb6d..16705611589a 100644
--- a/net/ieee802154/dgram.c
+++ b/net/ieee802154/dgram.c
@@ -230,6 +230,12 @@ static int dgram_sendmsg(struct kiocb *iocb, struct sock *sk,
 	mtu = dev->mtu;
 	pr_debug("name = %s, mtu = %u\n", dev->name, mtu);
 
+	if (size > mtu) {
+		pr_debug("size = %Zu, mtu = %u\n", size, mtu);
+		err = -EINVAL;
+		goto out_dev;
+	}
+
 	hlen = LL_RESERVED_SPACE(dev);
 	tlen = dev->needed_tailroom;
 	skb = sock_alloc_send_skb(sk, hlen + tlen + size,
@@ -258,12 +264,6 @@ static int dgram_sendmsg(struct kiocb *iocb, struct sock *sk,
 	if (err < 0)
 		goto out_skb;
 
-	if (size > mtu) {
-		pr_debug("size = %Zu, mtu = %u\n", size, mtu);
-		err = -EINVAL;
-		goto out_skb;
-	}
-
 	skb->dev = dev;
 	skb->sk  = sk;
 	skb->protocol = htons(ETH_P_IEEE802154);