net: qrtr: fix error return code of qrtr_sendmsg()

When sock_alloc_send_skb() returns NULL to skb, no error return code of
qrtr_sendmsg() is assigned.
To fix this bug, rc is assigned with -ENOMEM in this case.

Fixes: 194ccc88 ("net: qrtr: Support decoding incoming v2 packets")
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/qrtr/qrtr.c

@@ -958,8 +958,10 @@ static int qrtr_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
 	plen = (len + 3) & ~3;
 	skb = sock_alloc_send_skb(sk, plen + QRTR_HDR_MAX_SIZE,
 				  msg->msg_flags & MSG_DONTWAIT, &rc);
-	if (!skb)
+	if (!skb) {
+		rc = -ENOMEM;
 		goto out_node;
+	}
 
 	skb_reserve(skb, QRTR_HDR_MAX_SIZE);