The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f6f13c125e05603f68f5bf31f045b95e6d493598 Mon Sep 17 00:00:00 2001

From: Haiyang Zhang haiyangz@microsoft.com Date: Fri, 21 Feb 2020 08:32:18 -0800 Subject: [PATCH] hv_netvsc: Fix unwanted wakeup in netvsc_attach()

When netvsc_attach() is called by operations like changing MTU, etc., an extra wakeup may happen while netvsc_attach() calling rndis_filter_device_add() which sends rndis messages when queue is stopped in netvsc_detach(). The completion message will wake up queue 0.

We can reproduce the issue by changing MTU etc., then the wake_queue counter from "ethtool -S" will increase beyond stop_queue counter: stop_queue: 0 wake_queue: 1 The issue causes queue wake up, and counter increment, no other ill effects in current code. So we didn't see any network problem for now.

To fix this, initialize tx_disable to true, and set it to false when the NIC is ready to be attached or registered.

Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic") Signed-off-by: Haiyang Zhang haiyangz@microsoft.com Signed-off-by: David S. Miller davem@davemloft.net

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c index ae3f3084c2ed..1b320bcf150a 100644 --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -99,7 +99,7 @@ static struct netvsc_device *alloc_net_device(void)

init_waitqueue_head(&net_device->wait_drain); net_device->destroy = false; - net_device->tx_disable = false; + net_device->tx_disable = true;

net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT; net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT; diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 65e12cb07f45..2c0a24c606fc 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -1068,6 +1068,7 @@ static int netvsc_attach(struct net_device *ndev, }

/* In any case device is now ready */ + nvdev->tx_disable = false; netif_device_attach(ndev);

/* Note: enable and attach happen when sub-channels setup */ @@ -2476,6 +2477,8 @@ static int netvsc_probe(struct hv_device *dev, else net->max_mtu = ETH_DATA_LEN;

+ nvdev->tx_disable = false; + ret = register_netdevice(net); if (ret != 0) { pr_err("Unable to register netdev.\n");