Commit cd11acdd authored Jul 03, 2006 by Arjan van de Ven Committed by Linus Torvalds Jul 03, 2006

[PATCH] lockdep: annotate hostap netdev ->xmit_lock

On Fri, 2006-06-30 at 15:45 -0700, Miles Lane wrote:
> Okay, I rebuilt my kernel with your combo patch applied.
> Then, I inserted my US Robotics USR2210 PCMCIA wifi card,
> ran "pccardutil eject", popped out the card and then inserted
> a Compaq iPaq wifi card.  This triggered the following.
>
> [ INFO: possible circular locking dependency detected ]
> -------------------------------------------------------
> syslogd/1886 is trying to acquire lock:
>  (&dev->queue_lock){-+..}, at: [<c11a50b5>] dev_queue_xmit+0x120/0x24b
>
> but task is already holding lock:
>  (&dev->_xmit_lock){-+..}, at: [<c11a5118>] dev_queue_xmit+0x183/0x24b
>
> which lock already depends on the new lock.

ok this appears to be hostap playing games... it has 2 network devices
for one piece of hardware and one calls the other via the networking
layer; there is thankfully a natural ordering between the two, so just
making the slave one a separate type ought to make this work.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent a5b5bb9a

drivers/net/wireless/hostap/hostap_hw.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -3095,6 +3095,14 @@ static void prism2_clear_set_tim_queue(local_info_t *local)
		}


		/*
		* HostAP uses two layers of net devices, where the inner
		* layer gets called all the time from the outer layer.
		* This is a natural nesting, which needs a split lock type.
		*/
		static struct lock_class_key hostap_netdev_xmit_lock_key;


		static struct net_device *
		prism2_init_local_data(struct prism2_helper_functions *funcs, int card_idx,
		struct device *sdev)
		@@ -3259,6 +3267,8 @@ while (0)
		SET_NETDEV_DEV(dev, sdev);
		if (ret >= 0)
		ret = register_netdevice(dev);

		lockdep_set_class(&dev->_xmit_lock, &hostap_netdev_xmit_lock_key);
		rtnl_unlock();
		if (ret < 0) {
		printk(KERN_WARNING "%s: register netdevice failed!\n",