zap_completion_queue() retrieves skbs from completion_queue where they have
zero skb->users counter.  Before dev_kfree_skb_any() it should be non-zero
yet, so it's increased now.
Reported-and-tested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
                while (clist != NULL) {
                        struct sk_buff *skb = clist;
                        clist = clist->next;
-                       if (skb->destructor)
+                       if (skb->destructor) {
+                               atomic_inc(&skb->users);
                                dev_kfree_skb_any(skb); /* put this one back */
-                       else
+                       } else {
                                __kfree_skb(skb);
+                       }
                }
        }