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Commit 274c0422 authored by Dongli Zhang's avatar Dongli Zhang Committed by Greg Kroah-Hartman
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xen/netfront: stop tx queues during live migration 



[ Upstream commit 042b2046d0f05cf8124c26ff65dbb6148a4404fb ]

The tx queues are not stopped during the live migration. As a result, the
ndo_start_xmit() may access netfront_info->queues which is freed by
talk_to_netback()->xennet_destroy_queues().

This patch is to netif_device_detach() at the beginning of xen-netfront
resuming, and netif_device_attach() at the end of resuming.

     CPU A                                CPU B

 talk_to_netback()
 -> if (info->queues)
        xennet_destroy_queues(info);
    to free netfront_info->queues

                                        xennet_start_xmit()
                                        to access netfront_info->queues

  -> err = xennet_create_queues(info, &num_queues);

The idea is borrowed from virtio-net.

Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: default avatarDongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 5c6fb0e0

drivers/net/xen-netfront.c

+8 −0
Original line number Diff line number Diff line
@@ -1442,6 +1442,10 @@ static int netfront_resume(struct xenbus_device *dev) 


	dev_dbg(&dev->dev, "%s\n", dev->nodename);



	netif_tx_lock_bh(info->netdev);

	netif_device_detach(info->netdev);

	netif_tx_unlock_bh(info->netdev);



	xennet_disconnect_backend(info);

	return 0;

}
@@ -1990,6 +1994,10 @@ static int xennet_connect(struct net_device *dev) 
	 * domain a kick because we've probably just requeued some

	 * packets.

	 */

	netif_tx_lock_bh(np->netdev);

	netif_device_attach(np->netdev);

	netif_tx_unlock_bh(np->netdev);



	netif_carrier_on(np->netdev);

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

		queue = &np->queues[j];