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Date:   Mon, 4 Apr 2022 16:45:50 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Miaoqian Lin <linmq006@gmail.com>
Cc:     Jiri Slaby <jirislaby@kernel.org>, Joel Stanley <joel@jms.id.au>,
        Andrew Jeffery <andrew@aj.id.au>,
        Zev Weiss <zev@bewilderbeest.net>,
        Johan Hovold <johan@kernel.org>,
        Yang Guang <yang.guang5@zte.com.cn>,
        linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] serial: 8250_aspeed_vuart: Fix potential NULL
 dereference in aspeed_vuart_probe
Message-ID: <YksEnnyJDoL+fE5d@kroah.com>
References: <20220404143842.16960-1-linmq006@gmail.com>
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On Mon, Apr 04, 2022 at 02:38:40PM +0000, Miaoqian Lin wrote:
> platform_get_resource() may fail and return NULL, so we should
> better check it's return value to avoid a NULL pointer dereference.
> 
> Fixes: 54da3e381c2b ("serial: 8250_aspeed_vuart: use UPF_IOREMAP to set up register mapping")
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
> ---
>  drivers/tty/serial/8250/8250_aspeed_vuart.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c
> index 93fe10c680fb..9d2a7856784f 100644
> --- a/drivers/tty/serial/8250/8250_aspeed_vuart.c
> +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c
> @@ -429,6 +429,8 @@ static int aspeed_vuart_probe(struct platform_device *pdev)
>  	timer_setup(&vuart->unthrottle_timer, aspeed_vuart_unthrottle_exp, 0);
>  
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res)
> +		return -EINVAL;

How did you test this change was correct?