--- all/drivers/net/gianfar.c-orig
+++ all/drivers/net/gianfar.c

@@ -384,6 +384,8 @@
 	mii_info->mdio_read = &read_phy_reg;
 	mii_info->mdio_write = &write_phy_reg;
 
+        spin_lock_init(&mii_info->mdio_lock);
+
 	priv->mii_info = mii_info;
 
 	/* Reset the management interface */