@@ -3121,6 +3121,7 @@ int netdev_rx_handler_register(struct net_device *dev,
if (dev->rx_handler)
return -EBUSY;
+ /* Note: rx_handler_data must be set before rx_handler */
rcu_assign_pointer(dev->rx_handler_data, rx_handler_data);
rcu_assign_pointer(dev->rx_handler, rx_handler);
@@ -3141,6 +3142,11 @@ void netdev_rx_handler_unregister(struct net_device *dev)
ASSERT_RTNL();
RCU_INIT_POINTER(dev->rx_handler, NULL);
+ /* a reader seeing a non NULL rx_handler in a rcu_read_lock()
+ * section has a guarantee to see a non NULL rx_handler_data
+ * as well.
+ */
+ synchronize_net();
RCU_INIT_POINTER(dev->rx_handler_data, NULL);
}
EXPORT_SYMBOL_GPL(netdev_rx_handler_unregister);