| From 8eb4a8841f528c109749f02101dfb4a4c50d2f9c Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Fri, 22 Oct 2021 16:31:39 -0700 |
| Subject: xen/netfront: stop tx queues during live migration |
| |
| From: Dongli Zhang <dongli.zhang@oracle.com> |
| |
| [ 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: Dongli Zhang <dongli.zhang@oracle.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/net/xen-netfront.c | 8 ++++++++ |
| 1 file changed, 8 insertions(+) |
| |
| diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c |
| index 88280057e0321..7d389c2cc9026 100644 |
| --- a/drivers/net/xen-netfront.c |
| +++ b/drivers/net/xen-netfront.c |
| @@ -1439,6 +1439,10 @@ 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; |
| } |
| @@ -1987,6 +1991,10 @@ 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]; |
| -- |
| 2.33.0 |
| |
