net: qcom/emac: fix UAF in emac_remove

adpt is netdev private data and it cannot be
used after free_netdev() call. Using adpt after free_netdev()
can cause UAF bug. Fix it by moving free_netdev() at the end of the
function.

Fixes: 54e19bc ("net: qcom/emac: do not use devm on internal phy pdev")
Signed-off-by: Pavel Skripkin <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: pskrgag

drivers/net/ethernet/qualcomm/emac/emac.c

@@ -735,12 +735,13 @@ static int emac_remove(struct platform_device *pdev)
 
 	put_device(&adpt->phydev->mdio.dev);
 	mdiobus_unregister(adpt->mii_bus);
-	free_netdev(netdev);
 
 	if (adpt->phy.digital)
 		iounmap(adpt->phy.digital);
 	iounmap(adpt->phy.base);
 
+	free_netdev(netdev);
+
 	return 0;
 }