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.

And, move register_netdevice_notifier() earlier, so the call back function is set before probing.

Cc: stable@vger.kernel.org Fixes: e04e7a7bbd4b ("hv_netvsc: Fix a deadlock by getting rtnl lock earlier in netvsc_probe()") Signed-off-by: Haiyang Zhang haiyangz@microsoft.com

--- v2: Fix rtnl_unlock() in error handling as found by Wojciech Drewek. --- drivers/net/hyperv/netvsc_drv.c | 32 ++++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 3ba3c8fb28a5..1d1491da303b 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -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); @@ -2788,11 +2793,14 @@ static int __init netvsc_drv_init(void) } netvsc_ring_bytes = ring_size * PAGE_SIZE;

+ register_netdevice_notifier(&netvsc_netdev_notifier); + ret = vmbus_driver_register(&netvsc_drv); - if (ret) + if (ret) { + unregister_netdevice_notifier(&netvsc_netdev_notifier); return ret; + }

- register_netdevice_notifier(&netvsc_netdev_notifier); return 0; }