diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index a68aad4..8664fd2 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -102,6 +102,16 @@ struct netlink_ext_ack {
 		(extack)->bad_attr = (attr);		\
 } while (0)
 
+#define NL_SET_ERR_MSG_ATTR(extack, attr, msg) do {	\
+	static const char __msg[] = (msg);		\
+	struct netlink_ext_ack *__extack = (extack);	\
+							\
+	if (__extack) {					\
+		__extack->_msg = __msg;			\
+		__extack->bad_attr = (attr);		\
+	}						\
+} while (0)
+
 extern void netlink_kernel_release(struct sock *sk);
 extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
 extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);
diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h
index ca6f002..7c26863 100644
--- a/include/net/lwtunnel.h
+++ b/include/net/lwtunnel.h
@@ -35,7 +35,8 @@ struct lwtunnel_state {
 struct lwtunnel_encap_ops {
 	int (*build_state)(struct nlattr *encap,
 			   unsigned int family, const void *cfg,
-			   struct lwtunnel_state **ts);
+			   struct lwtunnel_state **ts,
+			   struct netlink_ext_ack *extack);
 	void (*destroy_state)(struct lwtunnel_state *lws);
 	int (*output)(struct net *net, struct sock *sk, struct sk_buff *skb);
 	int (*input)(struct sk_buff *skb);
@@ -114,7 +115,8 @@ int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
 int lwtunnel_build_state(u16 encap_type,
 			 struct nlattr *encap,
 			 unsigned int family, const void *cfg,
-			 struct lwtunnel_state **lws);
+			 struct lwtunnel_state **lws,
+			 struct netlink_ext_ack *extack);
 int lwtunnel_fill_encap(struct sk_buff *skb,
 			struct lwtunnel_state *lwtstate);
 int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate);
@@ -192,7 +194,8 @@ static inline int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
 static inline int lwtunnel_build_state(u16 encap_type,
 				       struct nlattr *encap,
 				       unsigned int family, const void *cfg,
-				       struct lwtunnel_state **lws)
+				       struct lwtunnel_state **lws,
+				       struct netlink_ext_ack *extack)
 {
 	return -EOPNOTSUPP;
 }