Re: [PATCH] bus: imx-weim: fix to avoid potential NULL pointer dereference

[Fabio Estevam]

Hi Zhang,

On Sat, Jul 15, 2023 at 12:21 PM Zhang Shurong
<zhang_shurong@xxxxxxxxxxx> wrote:
>
> of_match_device() may fail and returns a NULL pointer.
>
> Fix this by checking the return value of of_match_device.
>
> Fixes: 3f98b6baad63 ("drivers: bus: imx-weim: Add support for i.MX1/21/25/27/31/35/50/51/53")
> Signed-off-by: Zhang Shurong <zhang_shurong@xxxxxxxxxxx>
> ---
>  drivers/bus/imx-weim.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
> index 52a5d0447390..65402bb60c18 100644
> --- a/drivers/bus/imx-weim.c
> +++ b/drivers/bus/imx-weim.c
> @@ -202,15 +202,19 @@ static int weim_timing_setup(struct device *dev, struct device_node *np,
>
>  static int weim_parse_dt(struct platform_device *pdev)
>  {
> -       const struct of_device_id *of_id = of_match_device(weim_id_table,
> -                                                          &pdev->dev);
> -       const struct imx_weim_devtype *devtype = of_id->data;
> +       const struct of_device_id *of_id;
> +       const struct imx_weim_devtype *devtype;
>         int ret = 0, have_child = 0;
>         struct device_node *child;
>         struct weim_priv *priv;
>         void __iomem *base;
>         u32 reg;
>
> +       of_id = of_match_device(weim_id_table, &pdev->dev);
> +       if (!of_id)
> +               return -EINVAL;

If there is no match the driver will not probe in the first place.

I don't think this check is needed.