ixgbe: protect vxlan_get_rx_port in ixgbe_service_task with rtnl_lock

vxlan_get_rx_port requires rtnl_lock to be held.

Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Shannon Nelson <shannon.nelson@intel.com>
Cc: Carolyn Wyborny <carolyn.wyborny@intel.com>
Cc: Don Skidmore <donald.c.skidmore@intel.com>
Cc: Bruce Allan <bruce.w.allan@intel.com>
Cc: John Ronciak <john.ronciak@intel.com>
Cc: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -7192,10 +7192,12 @@ static void ixgbe_service_task(struct work_struct *work)
 		return;
 	}
 #ifdef CONFIG_IXGBE_VXLAN
+	rtnl_lock();
 	if (adapter->flags2 & IXGBE_FLAG2_VXLAN_REREG_NEEDED) {
 		adapter->flags2 &= ~IXGBE_FLAG2_VXLAN_REREG_NEEDED;
 		vxlan_get_rx_port(adapter->netdev);
 	}
+	rtnl_unlock();
 #endif /* CONFIG_IXGBE_VXLAN */
 	ixgbe_reset_subtask(adapter);
 	ixgbe_phy_interrupt_subtask(adapter);