Return-Path: From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Ake Koomsin , "David S . Miller" , Sasha Levin Subject: [PATCH AUTOSEL 4.18 28/33] virtio_net: avoid using netif_tx_disable() for serializing tx routine Date: Tue, 30 Oct 2018 09:26:52 -0400 Message-Id: <20181030132657.217970-28-sashal@kernel.org> In-Reply-To: <20181030132657.217970-1-sashal@kernel.org> References: <20181030132657.217970-1-sashal@kernel.org> List-ID: From: Ake Koomsin [ Upstream commit 05c998b738fdd3e5d6a257bcacc8f34b6284d795 ] 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() in case 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_bh()/netif_tx_unlock_bh() 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 Acked-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- 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 2b6ec927809e..500e2d8f10bc 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2162,8 +2162,9 @@ 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_bh(vi->dev); netif_device_detach(vi->dev); - netif_tx_disable(vi->dev); + netif_tx_unlock_bh(vi->dev); cancel_delayed_work_sync(&vi->refill); if (netif_running(vi->dev)) { @@ -2199,7 +2200,9 @@ static int virtnet_restore_up(struct virtio_device *vdev) } } + netif_tx_lock_bh(vi->dev); netif_device_attach(vi->dev); + netif_tx_unlock_bh(vi->dev); return err; } -- 2.17.1