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Commit ad068118 authored by David Vrabel's avatar David Vrabel Committed by David S. Miller
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xen-netfront: properly destroy queues when removing device 



xennet_remove() freed the queues before freeing the netdevice which
results in a use-after-free when free_netdev() tries to delete the
napi instances that have already been freed.

Fix this by fully destroy the queues (which includes deleting the napi
instances) before freeing the netdevice.

Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f4ecf29f

drivers/net/xen-netfront.c

+2 −13
Original line number Diff line number Diff line
@@ -1698,6 +1698,7 @@ static void xennet_destroy_queues(struct netfront_info *info) 


		if (netif_running(info->netdev))

			napi_disable(&queue->napi);

		del_timer_sync(&queue->rx_refill_timer);

		netif_napi_del(&queue->napi);

	}
@@ -2102,9 +2103,6 @@ static const struct attribute_group xennet_dev_group = { 
static int xennet_remove(struct xenbus_device *dev)

{

	struct netfront_info *info = dev_get_drvdata(&dev->dev);

	unsigned int num_queues = info->netdev->real_num_tx_queues;

	struct netfront_queue *queue = NULL;

	unsigned int i = 0;



	dev_dbg(&dev->dev, "%s\n", dev->nodename);
@@ -2112,16 +2110,7 @@ static int xennet_remove(struct xenbus_device *dev) 


	unregister_netdev(info->netdev);



	for (i = 0; i < num_queues; ++i) {

		queue = &info->queues[i];

		del_timer_sync(&queue->rx_refill_timer);

	}



	if (num_queues) {

		kfree(info->queues);

		info->queues = NULL;

	}



	xennet_destroy_queues(info);

	xennet_free_netdev(info->netdev);



	return 0;