[PATCH] check the return value of ndo_select_queue()

[Changli Gao <xiaosuo@gmail.com>]

check the return value of ndo_select_queue()

Check the return value of ndo_select_queue(). If the value isn't smaller
than the real_num_tx_queues, print a warning message, and reset it to zero.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
----
net/core/dev.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index b8f74cf..0a6bf2e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1794,10 +1794,17 @@ static struct netdev_queue *dev_pick_tx(struct net_device *dev,
 	const struct net_device_ops *ops = dev->netdev_ops;
 	u16 queue_index = 0;
 
-	if (ops->ndo_select_queue)
+	if (ops->ndo_select_queue) {
 		queue_index = ops->ndo_select_queue(dev, skb);
-	else if (dev->real_num_tx_queues > 1)
+		if (queue_index >= dev->real_num_tx_queues) {
+			WARN(1, "%s selects TX queue %d, "
+			     "but real number of TX queues is %d\n",
+			     dev->name, queue_index, dev->real_num_tx_queues);
+			queue_index = 0;
+		}
+	} else if (dev->real_num_tx_queues > 1) {
 		queue_index = skb_tx_hash(dev, skb);
+	}
 
 	skb_set_queue_mapping(skb, queue_index);
 	return netdev_get_tx_queue(dev, queue_index);