FAILED: patch "[PATCH] hv_netvsc: fix race of netvsc and VF register_netdevice" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-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 <[email protected]>.

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-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x d30fb712e52964f2cf9a9c14cf67078394044837
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023113020-shifter-qualifier-2df2@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

d30fb712e529 ("hv_netvsc: fix race of netvsc and VF register_netdevice") 351e1581395f ("hv_netvsc: Add XDP support")
0efeea5fb153 ("hv_netvsc: Add the support of hibernation") 719b85c336ed ("hv_netvsc: Fix error handling in netvsc_attach()") 68622d071e55 ("hv_netvsc: Sync offloading features to VF NIC") bf48648d650d ("hv_netvsc: Fix IP header checksum for coalesced packets") 52d3b4949192 ("hv_netvsc: fix typos in code comments") 17d912568984 ("hv_netvsc: Fix hash key value reset after other ops") 7c9f335a3ff2 ("hv_netvsc: Refactor assignments of struct netvsc_device_info") 2a7f8c3b1d3f ("hv_netvsc: remove ndo_poll_controller")

thanks,

greg k-h

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

From d30fb712e52964f2cf9a9c14cf67078394044837 Mon Sep 17 00:00:00 2001
From: Haiyang Zhang <[email protected]>
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.

index 3ba3c8fb28a5..5e528a76f5f5 100644
@@ -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);