diff --git a/net/netfilter/xt_qtaguid.c b/net/netfilter/xt_qtaguid.c
index 4429945e45c..4fac3712ebe 100644
--- a/net/netfilter/xt_qtaguid.c
+++ b/net/netfilter/xt_qtaguid.c
@@ -1710,6 +1710,10 @@ static struct sock *qtaguid_find_sk(const struct sk_buff *skb,
 	if (sk) {
 		MT_DEBUG("qtaguid[%d]: %p->sk_proto=%u->sk_state=%d\n",
 			 par->hooknum, sk, sk->sk_protocol, sk->sk_state);
+		/*
+		 * When in TCP_TIME_WAIT the sk is not a "struct sock" but
+		 * "struct inet_timewait_sock" which is missing fields.
+		 */
 		if (sk->sk_state  == TCP_TIME_WAIT) {
 			xt_socket_put_sk(sk);
 			sk = NULL;