lan78xx: Crash in lan78xx_writ_reg (Workqueue: events lan78xx_deferred_multicast_write)

Description:
Crash was reported with syzkaller pointing to lan78xx_write_reg routine.

Root-cause:
Proper cleanup of workqueues and init/setup routines was not happening
in failure conditions.

Fix:
Handled the error conditions by cleaning up the queues and init/setup
routines.

Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Raghuram Chary J <raghuramchary.jallipalli@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/lan78xx.c

@@ -2873,8 +2873,7 @@ static int lan78xx_bind(struct lan78xx_net *dev, struct usb_interface *intf)
 	if (ret < 0) {
 		netdev_warn(dev->net,
 			    "lan78xx_setup_irq_domain() failed : %d", ret);
-		kfree(pdata);
-		return ret;
+		goto out1;
 	}
 
 	dev->net->hard_header_len += TX_OVERHEAD;
@@ -2882,14 +2881,32 @@ static int lan78xx_bind(struct lan78xx_net *dev, struct usb_interface *intf)
 
 	/* Init all registers */
 	ret = lan78xx_reset(dev);
+	if (ret) {
+		netdev_warn(dev->net, "Registers INIT FAILED....");
+		goto out2;
+	}
 
 	ret = lan78xx_mdio_init(dev);
+	if (ret) {
+		netdev_warn(dev->net, "MDIO INIT FAILED.....");
+		goto out2;
+	}
 
 	dev->net->flags |= IFF_MULTICAST;
 
 	pdata->wol = WAKE_MAGIC;
 
 	return ret;
+
+out2:
+	lan78xx_remove_irq_domain(dev);
+
+out1:
+	netdev_warn(dev->net, "Bind routine FAILED");
+	cancel_work_sync(&pdata->set_multicast);
+	cancel_work_sync(&pdata->set_vlan);
+	kfree(pdata);
+	return ret;
 }
 
 static void lan78xx_unbind(struct lan78xx_net *dev, struct usb_interface *intf)
@@ -2901,6 +2918,8 @@ static void lan78xx_unbind(struct lan78xx_net *dev, struct usb_interface *intf)
 	lan78xx_remove_mdio(dev);
 
 	if (pdata) {
+		cancel_work_sync(&pdata->set_multicast);
+		cancel_work_sync(&pdata->set_vlan);
 		netif_dbg(dev, ifdown, dev->net, "free pdata");
 		kfree(pdata);
 		pdata = NULL;