net: add net device refcount tracker to struct netdev_queue

This will help debugging pesky netdev reference leaks.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

include/linux/netdevice.h

@@ -586,6 +586,8 @@ struct netdev_queue {
  * read-mostly part
  */
 	struct net_device	*dev;
+	netdevice_tracker	dev_tracker;
+
 	struct Qdisc __rcu	*qdisc;
 	struct Qdisc		*qdisc_sleeping;
 #ifdef CONFIG_SYSFS

net/core/net-sysfs.c

@@ -1607,7 +1607,7 @@ static void netdev_queue_release(struct kobject *kobj)
 	struct netdev_queue *queue = to_netdev_queue(kobj);
 
 	memset(kobj, 0, sizeof(*kobj));
-	dev_put(queue->dev);
+	dev_put_track(queue->dev, &queue->dev_tracker);
 }
 
 static const void *netdev_queue_namespace(struct kobject *kobj)
@@ -1647,7 +1647,7 @@ static int netdev_queue_add_kobject(struct net_device *dev, int index)
 	/* Kobject_put later will trigger netdev_queue_release call
 	 * which decreases dev refcount: Take that reference here
 	 */
-	dev_hold(queue->dev);
+	dev_hold_track(queue->dev, &queue->dev_tracker, GFP_KERNEL);
 
 	kobj->kset = dev->queues_kset;
 	error = kobject_init_and_add(kobj, &netdev_queue_ktype, NULL,