netpoll: Fix missing TXQ unlock and and OOPS.

The VLAN tag handling code in netpoll_send_skb_on_dev() has two problems.

1) It exits without unlocking the TXQ.

2) It then tries to queue a NULL skb to npinfo->txq.

Reported-by: Ahmed Tamrawi <atamrawi@iastate.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 2 deletions

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 8f971990677c..303097874633 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -386,8 +386,14 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
                                             !vlan_hw_offload_capable(netif_skb_features(skb),
                                                                      skb->vlan_proto)) {
                                                 skb = __vlan_put_tag(skb, skb->vlan_proto, vlan_tx_tag_get(skb));
-                                                if (unlikely(!skb))
-                                                        break;
+                                                if (unlikely(!skb)) {
+                                                        /* This is actually a packet drop, but we
+                                                         * don't want the code at the end of this
+                                                         * function to try and re-queue a NULL skb.
+                                                         */
+                                                        status = NETDEV_TX_OK;
+                                                        goto unlock_txq;
+                                                }
                                                 skb->vlan_tci = 0;
                                         }
 
@@ -395,6 +401,7 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
                                         if (status == NETDEV_TX_OK)
                                                 txq_trans_update(txq);
                                 }
+                        unlock_txq:
                                 __netif_tx_unlock(txq);
 
                                 if (status == NETDEV_TX_OK)