On 2018/10/17 下午3:59, Ake Koomsin wrote:
Commit 713a98d90c5e ("virtio-net: serialize tx routine during reset") introduces netif_tx_disable() after netif_device_detach() in order to avoid use-after-free of tx queues. However, there are two issues.1) Its operation is redundant with netif_device_detach() if the interface is running. 2) In case of the interface is not running before suspending and resuming, the tx does not get resumed by netif_device_attach(). This results in losing network connectivity. It is better to use netif_tx_lock()/netif_tx_unlock() instead for serializing tx routine during reset. This also preserves the symmetry of netif_device_detach() and netif_device_attach(). Fixes commit 713a98d90c5e ("virtio-net: serialize tx routine during reset") Signed-off-by: Ake Koomsin <[email protected]> --- drivers/net/virtio_net.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 3f5aa59c37b7..41ccf9c994a4 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2267,8 +2267,9 @@ static void virtnet_freeze_down(struct virtio_device *vdev) /* Make sure no work handler is accessing the device */ flush_work(&vi->config_work);+ netif_tx_lock(vi->dev);netif_device_detach(vi->dev); - netif_tx_disable(vi->dev); + netif_tx_unlock(vi->dev);
Sorry for not finding this earlier. I think we should use netif_tx_lock_bh() to prevent start_xmit() to run under bh.
Thanks
cancel_delayed_work_sync(&vi->refill);if (netif_running(vi->dev)) {@@ -2304,7 +2305,9 @@ static int virtnet_restore_up(struct virtio_device *vdev) } }+ netif_tx_lock(vi->dev);netif_device_attach(vi->dev); + netif_tx_unlock(vi->dev); return err; }
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