llc: fix another potential sk_buff leak in llc_ui_sendmsg()

All callers of llc_conn_state_process() except llc_build_and_send_pkt()
(via llc_ui_sendmsg() -> llc_ui_send_data()) assume that it always
consumes a reference to the skb.  Fix this caller to do the same.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
diff --git a/net/llc/llc_if.c b/net/llc/llc_if.c
index 8db03c2..ad65477 100644
--- a/net/llc/llc_if.c
+++ b/net/llc/llc_if.c
@@ -38,6 +38,8 @@
  *	closed and -EBUSY when sending data is not permitted in this state or
  *	LLC has send an I pdu with p bit set to 1 and is waiting for it's
  *	response.
+ *
+ *	This function always consumes a reference to the skb.
  */
 int llc_build_and_send_pkt(struct sock *sk, struct sk_buff *skb)
 {
@@ -46,20 +48,22 @@ int llc_build_and_send_pkt(struct sock *sk, struct sk_buff *skb)
 	struct llc_sock *llc = llc_sk(sk);
 
 	if (unlikely(llc->state == LLC_CONN_STATE_ADM))
-		goto out;
+		goto out_free;
 	rc = -EBUSY;
 	if (unlikely(llc_data_accept_state(llc->state) || /* data_conn_refuse */
 		     llc->p_flag)) {
 		llc->failed_data_req = 1;
-		goto out;
+		goto out_free;
 	}
 	ev = llc_conn_ev(skb);
 	ev->type      = LLC_CONN_EV_TYPE_PRIM;
 	ev->prim      = LLC_DATA_PRIM;
 	ev->prim_type = LLC_PRIM_TYPE_REQ;
 	skb->dev      = llc->dev;
-	rc = llc_conn_state_process(sk, skb);
-out:
+	return llc_conn_state_process(sk, skb);
+
+out_free:
+	kfree_skb(skb);
 	return rc;
 }