The patch below does not apply to the 5.10-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.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x d30fb712e52964f2cf9a9c14cf67078394044837 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023113018-crisply-tameness-85ee@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

d30fb712e529 ("hv_netvsc: fix race of netvsc and VF register_netdevice")

thanks,

greg k-h

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

From d30fb712e52964f2cf9a9c14cf67078394044837 Mon Sep 17 00:00:00 2001 From: Haiyang Zhang haiyangz@microsoft.com Date: Sun, 19 Nov 2023 08:23:41 -0800 Subject: [PATCH] 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: e04e7a7bbd4b ("hv_netvsc: Fix a deadlock by getting rtnl lock earlier in netvsc_probe()") Reported-by: Dexuan Cui decui@microsoft.com Signed-off-by: Haiyang Zhang haiyangz@microsoft.com Reviewed-by: Wojciech Drewek wojciech.drewek@intel.com Reviewed-by: Simon Horman horms@kernel.org Reviewed-by: Dexuan Cui decui@microsoft.com Signed-off-by: Paolo Abeni pabeni@redhat.com

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 3ba3c8fb28a5..5e528a76f5f5 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);