--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1083,6 +1113,7 @@ int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
 }
 
 EXPORT_SYMBOL(ip_cmsg_recv);
+EXPORT_SYMBOL(ip_cmsg_send);
 
 EXPORT_SYMBOL(ip_getsockopt);
 EXPORT_SYMBOL(ip_setsockopt);