From: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Date: Mon, 28 Mar 2016 17:41:18 -0300

+/* Polled functionality used by netconsole and others in non interrupt mode */
+static void mvneta_poll_controller(struct net_device *dev)
+{
+	struct mvneta_port *pp = netdev_priv(dev);
+
+	on_each_cpu(mvneta_percpu_poll_controller, pp, false);
+}

This doesn't work.

netpoll may be invoked from any context whatsoever, even hardware
interrupt handlers or contexts where cpu interrupts are disabled.

smp_call_function() and thus on_each_cpu() may not be called with
disabled interrupts or from a hardware interrupt handler or from
a bottom half handler, all of which are valid situations where
netpoll may occur since printk's can occur anywhere.