veth: Dont kfree_skb() after dev_forward_skb()

[ Upstream commit 6ec82562ffc6f297d0de36d65776cff8e5704867 ]

In case of congestion, netif_rx() frees the skb, so we must assume
dev_forward_skb() also consume skb.

Bug introduced by commit 445409602c092
(veth: move loopback logic to common location)

We must change dev_forward_skb() to always consume skb, and veth to not
double free it.

Bug report : http://marc.info/?l=linux-netdev&m=127310770900442&w=3

Reported-by: Martín Ferrari <martin.ferrari@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 3a15de56df9caa31b818139dbcd75e2dc99e5cc8..baf0b514092dc86e634d8beceb96135b64b83a25 100644 (file)
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -186,7 +186,6 @@ tx_drop:
        return NETDEV_TX_OK;
 
 rx_drop:
-       kfree_skb(skb);
        rcv_stats->rx_dropped++;
        return NETDEV_TX_OK;
 }

diff --git a/net/core/dev.c b/net/core/dev.c
index f51f940a077c1e345ca4ccc6c18693758d7b699e..cfd755705ee795d214c9471f5fba5a2fa32b3a2e 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1428,7 +1428,7 @@ static inline void net_timestamp(struct sk_buff *skb)
  *
  * return values:
  *     NET_RX_SUCCESS  (no congestion)
- *     NET_RX_DROP     (packet was dropped)
+ *     NET_RX_DROP     (packet was dropped, but freed)
  *
  * dev_forward_skb can be used for injecting an skb from the
  * start_xmit function of one device into the receive queue
@@ -1442,11 +1442,11 @@ int dev_forward_skb(struct net_device *dev, struct sk_buff *skb)
 {
        skb_orphan(skb);
 
-       if (!(dev->flags & IFF_UP))
-               return NET_RX_DROP;
-
-       if (skb->len > (dev->mtu + dev->hard_header_len))
+       if (!(dev->flags & IFF_UP) ||
+           (skb->len > (dev->mtu + dev->hard_header_len))) {
+               kfree_skb(skb);
                return NET_RX_DROP;
+       }
 
        skb_dst_drop(skb);
        skb->tstamp.tv64 = 0;