Liu Jian wrote:
> In sk_psock_backlog function, for ingress direction skb, if no new data
> packet arrives after the skb is cached, the cached skb does not have a
> chance to be added to the receive queue of psock. As a result, the cached
> skb cannot be received by the upper-layer application.
>
> Fix this by reschedule the psock work to dispose the cached skb in
> sk_msg_recvmsg function.
>
> Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
> Signed-off-by: Liu Jian <liujian56@xxxxxxxxxx>
> ---
Yep thanks. We have another fix coming for a similar case with ENOMEM
through backlog. I'll post here before end of week.
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
> net/core/skmsg.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/net/core/skmsg.c b/net/core/skmsg.c
> index 188f8558d27d..ca70525621c7 100644
> --- a/net/core/skmsg.c
> +++ b/net/core/skmsg.c
> @@ -434,8 +434,10 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
> if (copied + copy > len)
> copy = len - copied;
> copy = copy_page_to_iter(page, sge->offset, copy, iter);
> - if (!copy)
> - return copied ? copied : -EFAULT;
> + if (!copy) {
> + copied = copied ? copied : -EFAULT;
> + goto out;
> + }
>
> copied += copy;
> if (likely(!peek)) {
> @@ -455,7 +457,7 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
> * didn't copy the entire length lets just break.
> */
> if (copy != sge->length)
> - return copied;
> + goto out;
> sk_msg_iter_var_next(i);
> }
>
> @@ -477,7 +479,9 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
> }
> msg_rx = sk_psock_peek_msg(psock);
> }
> -
> +out:
> + if (psock->work_state.skb && copied > 0)
> + schedule_work(&psock->work);
> return copied;
> }
> EXPORT_SYMBOL_GPL(sk_msg_recvmsg);
> --
> 2.17.1
>
