diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
index 0ae67d537499..fffa3c4f456e 100644
--- a/net/ipv4/xfrm4_output.c
+++ b/net/ipv4/xfrm4_output.c
@@ -38,9 +38,12 @@ int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 
 void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
 {
+	struct sock *sk = skb_to_full_sk(skb);
 	struct iphdr *hdr;
 
+	if (!sk)
+		return;
+
 	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
-	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
-		       inet_sk(skb->sk)->inet_dport, mtu);
+	ip_local_error(sk, EMSGSIZE, hdr->daddr, inet_sk(sk)->inet_dport, mtu);
 }