Commit c457985a authored by Cong Wang's avatar Cong Wang Committed by Jakub Kicinski
Browse files

tcp: fix tcp_cleanup_rbuf() for tcp_read_skb() 



tcp_cleanup_rbuf() retrieves the skb from sk_receive_queue, it
assumes the skb is not yet dequeued. This is no longer true for
tcp_read_skb() case where we dequeue the skb first.

Fix this by introducing a helper __tcp_cleanup_rbuf() which does
not require any skb and calling it in tcp_read_skb().

Fixes: 04919bed ("tcp: Introduce tcp_read_skb()")
Cc: Eric Dumazet <edumazet@google.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: default avatarCong Wang <cong.wang@bytedance.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent e9c6e797

net/ipv4/tcp.c

+14 −10
Original line number Diff line number Diff line
@@ -1567,17 +1567,11 @@ static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len) 
 * calculation of whether or not we must ACK for the sake of

 * a window update.

 */

void tcp_cleanup_rbuf(struct sock *sk, int copied)

static void __tcp_cleanup_rbuf(struct sock *sk, int copied)

{

	struct tcp_sock *tp = tcp_sk(sk);

	bool time_to_ack = false;



	struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);



	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),

	     "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",

	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);



	if (inet_csk_ack_scheduled(sk)) {

		const struct inet_connection_sock *icsk = inet_csk(sk);
@@ -1623,6 +1617,17 @@ void tcp_cleanup_rbuf(struct sock *sk, int copied) 
		tcp_send_ack(sk);

}



void tcp_cleanup_rbuf(struct sock *sk, int copied)

{

	struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);

	struct tcp_sock *tp = tcp_sk(sk);



	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),

	     "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",

	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);

	__tcp_cleanup_rbuf(sk, copied);

}



static void tcp_eat_recv_skb(struct sock *sk, struct sk_buff *skb)

{

	__skb_unlink(skb, &sk->sk_receive_queue);
@@ -1771,20 +1776,19 @@ int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor) 
		copied += used;



		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {

			consume_skb(skb);

			++seq;

			break;

		}

		consume_skb(skb);

		break;

	}

	consume_skb(skb);

	WRITE_ONCE(tp->copied_seq, seq);



	tcp_rcv_space_adjust(sk);



	/* Clean up data we have read: This will do ACK frames. */

	if (copied > 0)

		tcp_cleanup_rbuf(sk, copied);

		__tcp_cleanup_rbuf(sk, copied);



	return copied;

}