Commit 20e7c4e8 authored Feb 10, 2014 by Eric Dumazet Committed by David S. Miller Feb 10, 2014

6lowpan: fix lockdep splats



When a device ndo_start_xmit() calls again dev_queue_xmit(),
lockdep can complain because dev_queue_xmit() is re-entered and the
spinlocks protecting tx queues share a common lockdep class.

Same issue was fixed for bonding/l2tp/ppp in commits

0daa2303 ("[PATCH] bonding: lockdep annotation")
49ee4920 ("bonding: set qdisc_tx_busylock to avoid LOCKDEP splat")
23d3b8bf ("net: qdisc busylock needs lockdep annotations ")
303c07db ("ppp: set qdisc_tx_busylock to avoid LOCKDEP splat ")

Reported-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 3e5ccc29

net/ieee802154/6lowpan.c

+20 −0

Original line number	Diff line number	Diff line
		@@ -530,7 +530,27 @@ static struct header_ops lowpan_header_ops = {
		.create = lowpan_header_create,
		};

		static struct lock_class_key lowpan_tx_busylock;
		static struct lock_class_key lowpan_netdev_xmit_lock_key;

		static void lowpan_set_lockdep_class_one(struct net_device *dev,
		struct netdev_queue *txq,
		void *_unused)
		{
		lockdep_set_class(&txq->_xmit_lock,
		&lowpan_netdev_xmit_lock_key);
		}


		static int lowpan_dev_init(struct net_device *dev)
		{
		netdev_for_each_tx_queue(dev, lowpan_set_lockdep_class_one, NULL);
		dev->qdisc_tx_busylock = &lowpan_tx_busylock;
		return 0;
		}

		static const struct net_device_ops lowpan_netdev_ops = {
		.ndo_init = lowpan_dev_init,
		.ndo_start_xmit = lowpan_xmit,
		.ndo_set_mac_address = lowpan_set_address,
		};