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References: <20211224082103.7658-1-linmq006@gmail.com>
In-Reply-To: <20211224082103.7658-1-linmq006@gmail.com>
From:   Chun-Kuang Hu <chunkuang.hu@kernel.org>
Date:   Fri, 31 Dec 2021 00:31:33 +0800
Message-ID: <CAAOTY_-7-BrnkPk_5V5y20F6fX3X8Vm0tcYAA=1DNCnxjvNF8A@mail.gmail.com>
Subject: Re: [PATCH] phy: mediatek: Fix missing check in mtk_mipi_tx_probe
To:     Miaoqian Lin <linmq006@gmail.com>
Cc:     Chun-Kuang Hu <chunkuang.hu@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Chunfeng Yun <chunfeng.yun@mediatek.com>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Vinod Koul <vkoul@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        linux-phy@lists.infradead.org,
        linux-kernel <linux-kernel@vger.kernel.org>
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Hi, Miaoqian:

Miaoqian Lin <linmq006@gmail.com> =E6=96=BC 2021=E5=B9=B412=E6=9C=8824=E6=
=97=A5 =E9=80=B1=E4=BA=94 =E4=B8=8B=E5=8D=884:21=E5=AF=AB=E9=81=93=EF=BC=9A
>
> The of_device_get_match_data() function may return NULL.
> Add check to prevent potential null dereference.
>
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
> ---
>  drivers/phy/mediatek/phy-mtk-mipi-dsi.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/phy/mediatek/phy-mtk-mipi-dsi.c b/drivers/phy/mediat=
ek/phy-mtk-mipi-dsi.c
> index 28ad9403c441..67b005d5b9e3 100644
> --- a/drivers/phy/mediatek/phy-mtk-mipi-dsi.c
> +++ b/drivers/phy/mediatek/phy-mtk-mipi-dsi.c
> @@ -146,6 +146,8 @@ static int mtk_mipi_tx_probe(struct platform_device *=
pdev)
>                 return -ENOMEM;
>
>         mipi_tx->driver_data =3D of_device_get_match_data(dev);
> +       if (!mipi_tx->driver_data)

I'm confused. mtk_mipi_tx_probe() is called because this device node's
compatible match one in mtk_mipi_tx_match[]. So I think the return
value of of_device_get_match_data(dev) would not be NULL. If this is
true, this checking is redundant.

Regards,
Chun-Kuang.

> +               return -ENODEV;
>
>         mipi_tx->regs =3D devm_platform_ioremap_resource(pdev, 0);
>         if (IS_ERR(mipi_tx->regs))
> --
> 2.17.1
>