Commit 1ca2983a authored by Wei Liu's avatar Wei Liu Committed by David S. Miller
Browse files

xen-netfront: avoid leaking resources when setup_netfront fails 



We should correctly free related resources (grant ref, memory page, evtchn)
when setup_netfront fails.

Signed-off-by: default avatarWei Liu <wei.liu2@citrix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6dffbe53

drivers/net/xen-netfront.c

+21 −12
Original line number Diff line number Diff line
@@ -1532,39 +1532,48 @@ static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info) 
	FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);



	err = xenbus_grant_ring(dev, virt_to_mfn(txs));

	if (err < 0) {

		free_page((unsigned long)txs);

		goto fail;

	}

	if (err < 0)

		goto grant_tx_ring_fail;



	info->tx_ring_ref = err;

	rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);

	if (!rxs) {

		err = -ENOMEM;

		xenbus_dev_fatal(dev, err, "allocating rx ring page");

		goto fail;

		goto alloc_rx_ring_fail;

	}

	SHARED_RING_INIT(rxs);

	FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);



	err = xenbus_grant_ring(dev, virt_to_mfn(rxs));

	if (err < 0) {

		free_page((unsigned long)rxs);

		goto fail;

	}

	if (err < 0)

		goto grant_rx_ring_fail;

	info->rx_ring_ref = err;



	err = xenbus_alloc_evtchn(dev, &info->evtchn);

	if (err)

		goto fail;

		goto alloc_evtchn_fail;



	err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt,

					0, netdev->name, netdev);

	if (err < 0)

		goto fail;

		goto bind_fail;

	netdev->irq = err;

	return 0;



	/* If we fail to setup netfront, it is safe to just revoke access to

	 * granted pages because backend is not accessing it at this point.

	 */

bind_fail:

	xenbus_free_evtchn(dev, info->evtchn);

alloc_evtchn_fail:

	gnttab_end_foreign_access_ref(info->rx_ring_ref, 0);

grant_rx_ring_fail:

	free_page((unsigned long)rxs);

alloc_rx_ring_fail:

	gnttab_end_foreign_access_ref(info->tx_ring_ref, 0);

grant_tx_ring_fail:

	free_page((unsigned long)txs);

fail:

	return err;

}