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References: <20211220081132.883709-1-jiasheng@iscas.ac.cn>
In-Reply-To: <20211220081132.883709-1-jiasheng@iscas.ac.cn>
From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Mon, 20 Dec 2021 09:29:56 +0100
Message-ID: <CAMuHMdWhs-wTcZNq2VrAZXrxeSNa88GR49j2rn5zSryxF4peOw@mail.gmail.com>
Subject: Re: [PATCH v2] video: fbdev: Check for null res pointer
To:     Jiasheng Jiang <jiasheng@iscas.ac.cn>
Cc:     s.hauer@pengutronix.de, kernel@pengutronix.de, shawnguo@kernel.org,
        festevam@gmail.com, linux-imx@nxp.com, linux-fbdev@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
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Precedence: bulk

Hi Jiasheng,

On Mon, Dec 20, 2021 at 9:19 AM Jiasheng Jiang <jiasheng@iscas.ac.cn> wrote:
> The return value of platform_get_resource() needs to be checked.
> To avoid use of error pointer in case that there is no suitable resource.

Thanks for your patch!

> Fixes: f7018c213502 ("video: move fbdev to drivers/video/fbdev")

That can't be the real introducer of the "bug"...

> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>

> --- a/drivers/video/fbdev/imxfb.c
> +++ b/drivers/video/fbdev/imxfb.c
> @@ -1083,6 +1083,8 @@ static int imxfb_remove(struct platform_device *pdev)
>         struct resource *res;
>
>         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       if (!res)
> +               return -EINVAL;

This cannot happen, as imxfb_remove() can only be called if
imxfb_probe() succeeded.  imxfb_probe() does check the result of
platform_get_resource(), and fails if the resource was not found.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds