hv_netvsc: fix bonding devices check in netvsc_netdev_event()

Bonding driver sets IFF_BONDING on both master (the bonding device) and
slave (the real NIC) devices and in netvsc_netdev_event() we want to skip
master devices only. Currently, there is an uncertainty when a slave
interface is removed: if bonding module comes first in netdev_chain it
clears IFF_BONDING flag on the netdev and netvsc_netdev_event() correctly
handles NETDEV_UNREGISTER event, but in case netvsc comes first on the
chain it sees the device with IFF_BONDING still attached and skips it. As
we still hold vf_netdev pointer to the device we crash on the next inject.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/hyperv/netvsc_drv.c

@@ -1482,8 +1482,13 @@ static int netvsc_netdev_event(struct notifier_block *this,
 {
 	struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
 
-	/* Avoid Vlan, Bonding dev with same MAC registering as VF */
-	if (event_dev->priv_flags & (IFF_802_1Q_VLAN | IFF_BONDING))
+	/* Avoid Vlan dev with same MAC registering as VF */
+	if (event_dev->priv_flags & IFF_802_1Q_VLAN)
+		return NOTIFY_DONE;
+
+	/* Avoid Bonding master dev with same MAC registering as VF */
+	if (event_dev->priv_flags & IFF_BONDING &&
+	    event_dev->flags & IFF_MASTER)
 		return NOTIFY_DONE;
 
 	switch (event) {