Re: imx6sx: Regression on FEC with KSZ8061

[Oleksij Rempel <o.rempel@pengutronix.de>]

On Wed, May 04, 2022 at 07:48:56AM -0300, Fabio Estevam wrote:
> On Wed, May 4, 2022 at 7:24 AM Fabio Estevam <festevam@gmail.com> wrote:
> >
> > Hi,
> >
> > On an imx6sx-based board, the Ethernet is functional on 5.10.
> >
> > The board has a KSZ8061 Ethernet PHY.
> >
> > After moving to kernel 5.15 or 5.17, the Ethernet is no longer functional:
> >
> > # udhcpc -i eth0
> > udhcpc: started, v1.35.0
> > 8<--- cut here ---
> > Unable to handle kernel NULL pointer dereference at virtual address 00000008
> > pgd = f73cef4e
> > [00000008] *pgd=00000000
> > Internal error: Oops: 5 [#1] SMP ARM
> > Modules linked in:
> > CPU: 0 PID: 196 Comm: ifconfig Not tainted 5.15.37-dirty #94
> > Hardware name: Freescale i.MX6 SoloX (Device Tree)
> > PC is at kszphy_config_reset+0x10/0x114
> 
> By adding this change, we can see that priv is NULL:
> 
> --- a/drivers/net/phy/micrel.c
> +++ b/drivers/net/phy/micrel.c
> @@ -508,8 +508,12 @@ static int kszphy_nand_tree_disable(struct phy_device *phyd
> ev)
>  /* Some config bits need to be set again on resume, handle them here. */
>  static int kszphy_config_reset(struct phy_device *phydev)
>  {
> -       struct kszphy_priv *priv = phydev->priv;
>         int ret;
> +       struct kszphy_priv *priv = phydev->priv;
> +       if (!priv) {
> +               pr_err("*********** priv is NULL\n");
> +               return -ENOMEM;
> +       }

Hm.. KSZ8061 do not calls probe, so priv is not allocated.

Regards,
Oleksij
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