From c457985aaa92e1fda2ce837cabf90bf687b92dcb Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Wed, 17 Aug 2022 12:54:43 -0700 Subject: [PATCH] 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: 04919bed948d ("tcp: Introduce tcp_read_skb()") Cc: Eric Dumazet Cc: John Fastabend Cc: Jakub Sitnicki Signed-off-by: Cong Wang Signed-off-by: Jakub Kicinski --- net/ipv4/tcp.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 05da5ca..181a0d3 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -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; } -- 2.7.4