Commit 8728c544 authored Apr 11, 2010 by Eric Dumazet Committed by David S. Miller Apr 15, 2010

net: dev_pick_tx() fix



When dev_pick_tx() caches tx queue_index on a socket, we must check
socket dst_entry matches skb one, or risk a crash later, as reported by
Denys Fedorysychenko, if old packets are in flight during a route
change, involving devices with different number of queues.

Bug introduced by commit a4ee3ce3
(net: Use sk_tx_queue_mapping for connected sockets)

Reported-by: Denys Fedorysychenko <nuclearcat@nuclearcat.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 4eaa0e3c

net/core/dev.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -1989,10 +1989,14 @@ static struct netdev_queue dev_pick_tx(struct net_device dev,
		if (dev->real_num_tx_queues > 1)
		queue_index = skb_tx_hash(dev, skb);

		if (sk && sk->sk_dst_cache)
		if (sk) {
		struct dst_entry *dst = rcu_dereference(sk->sk_dst_cache);

		if (dst && skb_dst(skb) == dst)
		sk_tx_queue_set(sk, queue_index);
		}
		}
		}

		skb_set_queue_mapping(skb, queue_index);
		return netdev_get_tx_queue(dev, queue_index);