[PATCH] tty/serial: digicolor: fix possible null-ptr-deref in digicolor_uart_probe()

[Baruch Siach]

Hi Yang,

On Thu, May 05 2022, Yang Yingliang wrote:
> It will cause null-ptr-deref when using 'res', if platform_get_resource()
> returns NULL, so move using 'res' after devm_ioremap_resource() that
> will check it to avoid null-ptr-deref.
> And use devm_platform_get_and_ioremap_resource() to simplify code.
>
> Fixes: 5930cb3511df ("serial: driver for Conexant Digicolor USART")
> Signed-off-by: Yang Yingliang <yangyingliang at huawei.com>

Reviewed-by: Baruch Siach <baruch at tkos.co.il>

Thanks,
baruch

> ---
>  drivers/tty/serial/digicolor-usart.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/tty/serial/digicolor-usart.c b/drivers/tty/serial/digicolor-usart.c
> index 6d70fea76bb3..e37a917b9dbb 100644
> --- a/drivers/tty/serial/digicolor-usart.c
> +++ b/drivers/tty/serial/digicolor-usart.c
> @@ -471,11 +471,10 @@ static int digicolor_uart_probe(struct platform_device *pdev)
>  	if (IS_ERR(uart_clk))
>  		return PTR_ERR(uart_clk);
>  
> -	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -	dp->port.mapbase = res->start;
> -	dp->port.membase = devm_ioremap_resource(&pdev->dev, res);
> +	dp->port.membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
>  	if (IS_ERR(dp->port.membase))
>  		return PTR_ERR(dp->port.membase);
> +	dp->port.mapbase = res->start;
>  
>  	irq = platform_get_irq(pdev, 0);
>  	if (irq < 0)


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