This is a note to let you know that I've just added the patch titled xen/netfront: stop tx queues during live migration to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xen-netfront-stop-tx-queues-during-live-migration.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit a27f6fcf61d0592961f999baa0cf13182d1a3a62 Author: Dongli Zhang <dongli.zhang@xxxxxxxxxx> Date: Fri Oct 22 16:31:39 2021 -0700 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@xxxxxxxxxx> Signed-off-by: Dongli Zhang <dongli.zhang@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index ceaf6b30d683d..0971c09363cbf 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -1460,6 +1460,10 @@ 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; } @@ -2020,6 +2024,10 @@ 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];