[PATCH] iommu/mediatek: check return value after calling platform_get_resource()

[Matthias Brugger]

On 29/10/2022 12:35, Yang Yingliang wrote:
> platform_get_resource() may return NULL pointer, we need check its
> return value to avoid null-ptr-deref in resource_size().
> 
> Fixes: 42d57fc58aeb ("iommu/mediatek: Initialise/Remove for multi bank dev")
> Signed-off-by: Yang Yingliang <yangyingliang at huawei.com>
> ---
>   drivers/iommu/mtk_iommu.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 2ab2ecfe01f8..2d14dc846b83 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -1173,6 +1173,8 @@ static int mtk_iommu_probe(struct platform_device *pdev)
>   
>   	banks_num = data->plat_data->banks_num;
>   	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res)
> +		return -EINVAL;

That would be the case if the DT passed to the kernel isn't correct, but anyway:

Reviewed-by: Matthias Brugger <matthias.bgg at gmail.com>

>   	if (resource_size(res) < banks_num * MTK_IOMMU_BANK_SZ) {
>   		dev_err(dev, "banknr %d. res %pR is not enough.\n", banks_num, res);
>   		return -EINVAL;