xen-netfront: Improve error handling during initialization (e2e004ac) · Commits · 戴 / test

This fixes a crash when running out of grant refs when creating many queues across many netdevs. * If creating queues fails (i.e. there are no grant refs available), call xenbus_dev_fatal() to ensure that the xenbus device is set to the closed state. * If no queues are created, don't call xennet_disconnect_backend as netdev->real_num_tx_queues will not have been set correctly. * If setup_netfront() fails, ensure that all the queues created are cleaned up, not just those that have been set up. * If any queues were set up and an error occurs, call xennet_destroy_queues() to clean up the napi context. * If any fatal error occurs, unregister and destroy the netdev to avoid leaving around a half setup network device. Signed-off-by:

Ross Lagerwall <ross.lagerwall@citrix.com> Reviewed-by:

Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/xen-netfront.c

+11 −18

Original line number	Diff line number	Diff line
		@@ -1830,27 +1830,19 @@ static int talk_to_netback(struct xenbus_device *dev,
		xennet_destroy_queues(info);

		err = xennet_create_queues(info, &num_queues);
		if (err < 0)
		goto destroy_ring;
		if (err < 0) {
		xenbus_dev_fatal(dev, err, "creating queues");
		kfree(info->queues);
		info->queues = NULL;
		goto out;
		}

		/* Create shared ring, alloc event channel -- for each queue */
		for (i = 0; i < num_queues; ++i) {
		queue = &info->queues[i];
		err = setup_netfront(dev, queue, feature_split_evtchn);
		if (err) {
		/* setup_netfront() will tidy up the current
		* queue on error, but we need to clean up
		* those already allocated.
		*/
		if (i > 0) {
		rtnl_lock();
		netif_set_real_num_tx_queues(info->netdev, i);
		rtnl_unlock();
		if (err)
		goto destroy_ring;
		} else {
		goto out;
		}
		}
		}

		again:
		@@ -1940,9 +1932,10 @@ abort_transaction_no_dev_fatal:
		xenbus_transaction_end(xbt, 1);
		destroy_ring:
		xennet_disconnect_backend(info);
		kfree(info->queues);
		info->queues = NULL;
		xennet_destroy_queues(info);
		out:
		unregister_netdev(info->netdev);
		xennet_free_netdev(info->netdev);
		return err;
		}

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