From: Yang Yingliang <yangyingliang@xxxxxxxxxx> commit 447ee1516f19f534a228dda237eddb202f23e163 upstream. 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@xxxxxxxxxx> Reviewed-by: Baruch Siach <baruch@xxxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220505124621.1592697-1-yangyingliang@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/digicolor-usart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/tty/serial/digicolor-usart.c +++ b/drivers/tty/serial/digicolor-usart.c @@ -472,10 +472,10 @@ static int digicolor_uart_probe(struct p 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); 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)