Subject: Re: [PATCH net] net: mdio: Check regmap pointer returned by device_node_to_regmap()

From: Christian Marangi <[email-masked]>
Date: Tue, 4 Nov 2025 13:01:15 +0100

On Fri, Oct 31, 2025 at 09:15:53AM -0700, Alok Tiwari wrote:
> The call to device_node_to_regmap() in airoha_mdio_probe() can return
> an ERR_PTR() if regmap initialization fails. Currently, the driver
> stores the pointer without validation, which could lead to a crash
> if it is later dereferenced.
> 
> Add an IS_ERR() check and return the corresponding error code to make
> the probe path more robust.
> 
> Fixes: 67e3ba978361 ("net: mdio: Add MDIO bus controller for Airoha AN7583")
> Signed-off-by: Alok Tiwari <[email-masked]>

Thanks for taking care. It goes against the schema but yep it's a corner
case that should be handled.

> ---
>  drivers/net/mdio/mdio-airoha.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/mdio/mdio-airoha.c b/drivers/net/mdio/mdio-airoha.c
> index 1dc9939c8d7d..52e7475121ea 100644
> --- a/drivers/net/mdio/mdio-airoha.c
> +++ b/drivers/net/mdio/mdio-airoha.c
> @@ -219,6 +219,8 @@ static int airoha_mdio_probe(struct platform_device *pdev)
>  	priv = bus->priv;
>  	priv->base_addr = addr;
>  	priv->regmap = device_node_to_regmap(dev->parent->of_node);
> +	if (IS_ERR(priv->regmap))
> +		return PTR_ERR(priv->regmap);
>  
>  	priv->clk = devm_clk_get_enabled(dev, NULL);
>  	if (IS_ERR(priv->clk))
> -- 
> 2.50.1
> 

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