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authorPaul Durrant <Paul.Durrant@citrix.com>2016-10-07 11:32:31 +0300
committerDavid S. Miller <davem@davemloft.net>2016-10-08 06:52:33 +0300
commit912e27e85e070596ed4964ebde29fa9781390f2a (patch)
treedba537c23128bb30cba34fb2453edb6752e03102
parent21d9629a7abd87512d062fbe57b04a1baedf93d2 (diff)
downloadlinux-912e27e85e070596ed4964ebde29fa9781390f2a.tar.xz
xen-netback: make sure that hashes are not send to unaware frontends
In the case when a frontend only negotiates a single queue with xen- netback it is possible for a skbuff with a s/w hash to result in a hash extra_info segment being sent to the frontend even when no hash algorithm has been configured. (The ndo_select_queue() entry point makes sure the hash is not set if no algorithm is configured, but this entry point is not called when there is only a single queue). This can result in a frontend that is unable to handle extra_info segments being given such a segment, causing it to crash. This patch fixes the problem by clearing the hash in ndo_start_xmit() instead, which is clearly guaranteed to be called irrespective of the number of queues. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/xen-netback/interface.c20
1 files changed, 9 insertions, 11 deletions
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 4af532a67d95..74dc2bf71428 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -149,17 +149,8 @@ static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
struct xenvif *vif = netdev_priv(dev);
unsigned int size = vif->hash.size;
- if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE) {
- u16 index = fallback(dev, skb) % dev->real_num_tx_queues;
-
- /* Make sure there is no hash information in the socket
- * buffer otherwise it would be incorrectly forwarded
- * to the frontend.
- */
- skb_clear_hash(skb);
-
- return index;
- }
+ if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
+ return fallback(dev, skb) % dev->real_num_tx_queues;
xenvif_set_skb_hash(vif, skb);
@@ -208,6 +199,13 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
cb = XENVIF_RX_CB(skb);
cb->expires = jiffies + vif->drain_timeout;
+ /* If there is no hash algorithm configured then make sure there
+ * is no hash information in the socket buffer otherwise it
+ * would be incorrectly forwarded to the frontend.
+ */
+ if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
+ skb_clear_hash(skb);
+
xenvif_rx_queue_tail(queue, skb);
xenvif_kick_thread(queue);