net: fec: fix use-after-free in fec_drv_remove

Smatch says:
	drivers/net/ethernet/freescale/fec_main.c:3994 fec_drv_remove() error: Using fep after free_{netdev,candev}(ndev);
	drivers/net/ethernet/freescale/fec_main.c:3995 fec_drv_remove() error: Using fep after free_{netdev,candev}(ndev);

Since fep pointer is netdev private data, accessing it after free_netdev()
call can cause use-after-free bug. Fix it by moving free_netdev() call at
the end of the function

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: a31eda65ba21 ("net: fec: fix clock count mis-match")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Reviewed-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 8aea707..7e4c498 100644 (file)
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -3843,13 +3843,13 @@ fec_drv_remove(struct platform_device *pdev)
        if (of_phy_is_fixed_link(np))
                of_phy_deregister_fixed_link(np);
        of_node_put(fep->phy_node);
-       free_netdev(ndev);
 
        clk_disable_unprepare(fep->clk_ahb);
        clk_disable_unprepare(fep->clk_ipg);
        pm_runtime_put_noidle(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
 
+       free_netdev(ndev);
        return 0;
 }