On Wed, Jan 08, 2020 at 12:57:08PM +0800, Lingpeng Chen wrote:
> Right now in tcp_bpf_recvmsg, sock read data first from sk_receive_queue
> if not empty than psock->ingress_msg otherwise. If a FIN packet arrives
> and there's also some data in psock->ingress_msg, the data in
> psock->ingress_msg will be purged. It is always happen when request to a
> HTTP1.0 server like python SimpleHTTPServer since the server send FIN
> packet after data is sent out.
>
> Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface")
> Reported-by: Arika Chen <eaglesora@xxxxxxxxx>
> Suggested-by: Arika Chen <eaglesora@xxxxxxxxx>
> Signed-off-by: Lingpeng Chen <forrest0579@xxxxxxxxx>
> Signed-off-by: John Fastabend <john.fastabend@xxxxxxxxx>
> ---
> net/ipv4/tcp_bpf.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
> index e38705165ac9..f7e902868fce 100644
> --- a/net/ipv4/tcp_bpf.c
> +++ b/net/ipv4/tcp_bpf.c
> @@ -123,12 +123,13 @@ int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
>
> if (unlikely(flags & MSG_ERRQUEUE))
> return inet_recv_error(sk, msg, len, addr_len);
Shouldn't we also move the error queue handling below the psock test as
well and let tcp_recvmsg() natively do it in case of !psock?
> - if (!skb_queue_empty(&sk->sk_receive_queue))
> - return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
>
> psock = sk_psock_get(sk);
> if (unlikely(!psock))
> return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
> + if (!skb_queue_empty(&sk->sk_receive_queue) &&
> + sk_psock_queue_empty(psock))
> + return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
> lock_sock(sk);
> msg_bytes_ready:
> copied = __tcp_bpf_recvmsg(sk, psock, msg, len, flags);
> @@ -139,7 +140,7 @@ int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
> timeo = sock_rcvtimeo(sk, nonblock);
> data = tcp_bpf_wait_data(sk, psock, flags, timeo, &err);
> if (data) {
> - if (skb_queue_empty(&sk->sk_receive_queue))
> + if (!sk_psock_queue_empty(psock))
> goto msg_bytes_ready;
> release_sock(sk);
> sk_psock_put(sk, psock);
> --
> 2.17.1
>
