Commit d30fb712 authored by Haiyang Zhang's avatar Haiyang Zhang Committed by Paolo Abeni
Browse files

hv_netvsc: fix race of netvsc and VF register_netdevice 



The rtnl lock also needs to be held before rndis_filter_device_add()
which advertises nvsp_2_vsc_capability / sriov bit, and triggers
VF NIC offering and registering. If VF NIC finished register_netdev()
earlier it may cause name based config failure.

To fix this issue, move the call to rtnl_lock() before
rndis_filter_device_add(), so VF will be registered later than netvsc
/ synthetic NIC, and gets a name numbered (ethX) after netvsc.

Cc: stable@vger.kernel.org
Fixes: e04e7a7b ("hv_netvsc: Fix a deadlock by getting rtnl lock earlier in netvsc_probe()")
Reported-by: default avatarDexuan Cui <decui@microsoft.com>
Signed-off-by: default avatarHaiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: default avatarWojciech Drewek <wojciech.drewek@intel.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Reviewed-by: default avatarDexuan Cui <decui@microsoft.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent c0e29262

drivers/net/hyperv/netvsc_drv.c

+15 −10
Original line number Diff line number Diff line
@@ -2531,15 +2531,6 @@ static int netvsc_probe(struct hv_device *dev, 
		goto devinfo_failed;

	}



	nvdev = rndis_filter_device_add(dev, device_info);

	if (IS_ERR(nvdev)) {

		ret = PTR_ERR(nvdev);

		netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);

		goto rndis_failed;

	}



	eth_hw_addr_set(net, device_info->mac_adr);



	/* We must get rtnl lock before scheduling nvdev->subchan_work,

	 * otherwise netvsc_subchan_work() can get rtnl lock first and wait

	 * all subchannels to show up, but that may not happen because
@@ -2547,9 +2538,23 @@ static int netvsc_probe(struct hv_device *dev, 
	 * -> ... -> device_add() -> ... -> __device_attach() can't get

	 * the device lock, so all the subchannels can't be processed --

	 * finally netvsc_subchan_work() hangs forever.

	 *

	 * The rtnl lock also needs to be held before rndis_filter_device_add()

	 * which advertises nvsp_2_vsc_capability / sriov bit, and triggers

	 * VF NIC offering and registering. If VF NIC finished register_netdev()

	 * earlier it may cause name based config failure.

	 */

	rtnl_lock();



	nvdev = rndis_filter_device_add(dev, device_info);

	if (IS_ERR(nvdev)) {

		ret = PTR_ERR(nvdev);

		netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);

		goto rndis_failed;

	}



	eth_hw_addr_set(net, device_info->mac_adr);



	if (nvdev->num_chn > 1)

		schedule_work(&nvdev->subchan_work);
@@ -2586,9 +2591,9 @@ static int netvsc_probe(struct hv_device *dev, 
	return 0;



register_failed:

	rtnl_unlock();

	rndis_filter_device_remove(dev, nvdev);

rndis_failed:

	rtnl_unlock();

	netvsc_devinfo_put(device_info);

devinfo_failed:

	free_percpu(net_device_ctx->vf_stats);