[PATCH net] hyperv: Fix race between probe and open calls

[Haiyang Zhang]

Moving the register_netdev to the end of probe to prevent
possible open call happens before NetVSP is connected.

Signed-off-by: Haiyang Zhang <haiya...@microsoft.com>
Reviewed-by: K. Y. Srinivasan <k...@microsoft.com>
---
 drivers/net/hyperv/netvsc_drv.c |   20 ++++++++------------
 1 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index f813572..71baeb3 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -261,9 +261,7 @@ int netvsc_recv_callback(struct hv_device *device_obj,
        struct sk_buff *skb;
 
        net = ((struct netvsc_device *)hv_get_drvdata(device_obj))->ndev;
-       if (!net) {
-               netdev_err(net, "got receive callback but net device"
-                       " not initialized yet\n");
+       if (!net || net->reg_state != NETREG_REGISTERED) {
                packet->status = NVSP_STAT_FAIL;
                return 0;
        }
@@ -435,19 +433,11 @@ static int netvsc_probe(struct hv_device *dev,
        SET_ETHTOOL_OPS(net, &ethtool_ops);
        SET_NETDEV_DEV(net, &dev->device);
 
-       ret = register_netdev(net);
-       if (ret != 0) {
-               pr_err("Unable to register netdev.\n");
-               free_netdev(net);
-               goto out;
-       }
-
        /* Notify the netvsc driver of the new device */
        device_info.ring_size = ring_size;
        ret = rndis_filter_device_add(dev, &device_info);
        if (ret != 0) {
                netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
-               unregister_netdev(net);
                free_netdev(net);
                hv_set_drvdata(dev, NULL);
                return ret;
@@ -456,7 +446,13 @@ static int netvsc_probe(struct hv_device *dev,
 
        netif_carrier_on(net);
 
-out:
+       ret = register_netdev(net);
+       if (ret != 0) {
+               pr_err("Unable to register netdev.\n");
+               rndis_filter_device_remove(dev);
+               free_netdev(net);
+       }
+
        return ret;
 }
 
-- 
1.7.4.1

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