diff mbox series

[1/3] hv_netvsc: fix race of netvsc and VF register_netdevice

Message ID 20231128201606.940649-2-tim.gardner@canonical.com
State New
Headers show
Series Azure: Deprecate Netvsc and implement MANA direct | expand

Commit Message

Tim Gardner Nov. 28, 2023, 8:16 p.m. UTC 
From: Haiyang Zhang <haiyangz@microsoft.com>

BugLink: https://bugs.launchpad.net/bugs/2045069

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>
(cherry picked from commit d30fb712e52964f2cf9a9c14cf67078394044837)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---
 drivers/net/hyperv/netvsc_drv.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 664a30aa46ea..e247cd70e8a9 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2525,15 +2525,6 @@  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;
-	}
-
-	memcpy(net->dev_addr, device_info->mac_adr, ETH_ALEN);
-
 	/* 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
@@ -2541,9 +2532,23 @@  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;
+	}
+
+	memcpy(net->dev_addr, device_info->mac_adr, ETH_ALEN);
+
 	if (nvdev->num_chn > 1)
 		schedule_work(&nvdev->subchan_work);
 
@@ -2577,9 +2582,9 @@  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);