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From:   Kevin Tang <kevin3.tang@gmail.com>
Date:   Sun, 19 Dec 2021 00:23:07 +0800
Message-ID: <CAFPSGXZLWmahF+ptQC2TT84rB6E0v=V2c6ETkKAd4GKP3c756A@mail.gmail.com>
Subject: Re: [PATCH -next] drm/sprd: fix potential NULL dereference
To:     Zou Wei <zou_wei@huawei.com>
Cc:     airlied@linux.ie, daniel@ffwll.ch, orsonzhai@gmail.com,
        baolin.wang7@gmail.com, zhang.lyra@gmail.com,
        maarten.lankhorst@linux.intel.com, maxime@cerno.tech,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
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Dear Wei,
Thank you for your notice. I have received it. I will be fix it later.

Best wishes

Zou Wei <zou_wei@huawei.com> =E4=BA=8E2021=E5=B9=B412=E6=9C=8814=E6=97=A5=
=E5=91=A8=E4=BA=8C 17:11=E5=86=99=E9=81=93=EF=BC=9A
>
> platform_get_resource() may fail and return NULL, so we should
> better check it's return value to avoid a NULL pointer dereference
> a bit later in the code.
>
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Zou Wei <zou_wei@huawei.com>
> ---
>  drivers/gpu/drm/sprd/sprd_dpu.c | 2 ++
>  drivers/gpu/drm/sprd/sprd_dsi.c | 2 ++
>  2 files changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/sprd/sprd_dpu.c b/drivers/gpu/drm/sprd/sprd_=
dpu.c
> index 06a3414..920cb7d 100644
> --- a/drivers/gpu/drm/sprd/sprd_dpu.c
> +++ b/drivers/gpu/drm/sprd/sprd_dpu.c
> @@ -790,6 +790,8 @@ static int sprd_dpu_context_init(struct sprd_dpu *dpu=
,
>         int ret;
>
>         res =3D platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       if (!res)
> +               return -EINVAL;
>         ctx->base =3D devm_ioremap(dev, res->start, resource_size(res));
>         if (!ctx->base) {
>                 dev_err(dev, "failed to map dpu registers\n");
> diff --git a/drivers/gpu/drm/sprd/sprd_dsi.c b/drivers/gpu/drm/sprd/sprd_=
dsi.c
> index 911b3cd..c90a950 100644
> --- a/drivers/gpu/drm/sprd/sprd_dsi.c
> +++ b/drivers/gpu/drm/sprd/sprd_dsi.c
> @@ -907,6 +907,8 @@ static int sprd_dsi_context_init(struct sprd_dsi *dsi=
,
>         struct resource *res;
>
>         res =3D platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       if (!res)
> +               return -EINVAL;
>         ctx->base =3D devm_ioremap(dev, res->start, resource_size(res));
>         if (!ctx->base) {
>                 drm_err(dsi->drm, "failed to map dsi host registers\n");
> --
> 2.6.2
>