4.14-stable review patch. If anyone has any objections, please let me know.
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From: Paolo Abeni pabeni@redhat.com
[ Upstream commit 0b91bce1ebfc797ff3de60c8f4a1e6219a8a3187 ]
Christoph reported a stall while peeking datagram with an offset when busy polling is enabled. __skb_try_recv_datagram() uses as the loop termination condition 'queue empty'. When peeking, the socket queue can be not empty, even when no additional packets are received.
Address the issue explicitly checking for receive queue changes, as currently done by __skb_wait_for_more_packets().
Fixes: 2b5cd0dfa384 ("net: Change return type of sk_busy_loop from bool to void") Reported-and-tested-by: Christoph Paasch cpaasch@apple.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/datagram.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -281,7 +281,7 @@ struct sk_buff *__skb_try_recv_datagram( break;
sk_busy_loop(sk, flags & MSG_DONTWAIT); - } while (!skb_queue_empty(&sk->sk_receive_queue)); + } while (sk->sk_receive_queue.prev != *last);
error = -EAGAIN;