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

1 files changed, 15 insertions, 0 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 548340b57296..32045df1da5c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1848,6 +1848,20 @@ u16 skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb)
 }
 EXPORT_SYMBOL(skb_tx_hash);
 
+static inline u16 dev_cap_txqueue(struct net_device *dev, u16 queue_index)
+{
+        if (unlikely(queue_index >= dev->real_num_tx_queues)) {
+                if (net_ratelimit()) {
+                        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);
+                }
+                return 0;
+        }
+        return queue_index;
+}
+
 static struct netdev_queue *dev_pick_tx(struct net_device *dev,
                                         struct sk_buff *skb)
 {
@@ -1861,6 +1875,7 @@ static struct netdev_queue *dev_pick_tx(struct net_device *dev,
 
                 if (ops->ndo_select_queue) {
                         queue_index = ops->ndo_select_queue(dev, skb);
+                        queue_index = dev_cap_txqueue(dev, queue_index);
                 } else {
                         queue_index = 0;
                         if (dev->real_num_tx_queues > 1)