Re: [PATCH net 1/3] net: fealnx: fix teardown order in remove

[Andrew Lunn]

On Thu, Sep 24, 2026 at 10:44:21AM +0000, Жамбакиев Радий Рикардинович wrote:
> From: Radiy Zhambakiev <r.zhambakiev@xxxxxxxxxxxxxxxxx>
> 
> fealnx_remove_one() frees the DMA rings before unregistering the
> netdev, while the interface may still be up, which leaves a
> window where freed memory can be accessed.
> 
> Call unregister_netdev() first so dev_close() stops the Tx/Rx
> engines, deletes the timers, and frees the IRQ before the rings are
> freed. While at it use dev_err() instead of printk() for the 
> unknown-device case.
> 
> Found by Linux Verification Center (linuxtesting.org)
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Radiy Zhambakiev <r.zhambakiev@xxxxxxxxxxxxxxxxx>
> ---
>  drivers/net/ethernet/fealnx.c | 29 ++++++++++++++++-------------
>  1 file changed, 16 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/net/ethernet/fealnx.c b/drivers/net/ethernet/fealnx.c
> index bdc38aac5850..d7cd1644a375 100644
> --- a/drivers/net/ethernet/fealnx.c
> +++ b/drivers/net/ethernet/fealnx.c
> @@ -678,20 +678,23 @@ static int fealnx_init_one(struct pci_dev *pdev,
>  static void fealnx_remove_one(struct pci_dev *pdev)
>  {
>  	struct net_device *dev = pci_get_drvdata(pdev);
> +	struct netdev_private *np;
> +
> +	if (!dev) {
> +		dev_err(&pdev->dev, "remove for unknown device\n");
> +		return;
> +	}

I know you are just moving code around, but is that possible?  We try
avoid defensive code. It is better to actually understand the code and
stop bad things happening.

     Andrew