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: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 1db10141..5770e3b 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1532,40 +1532,49 @@
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;
- fail:
+ /* 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;
}