Re: [PATCH -next] drm/meson: Fix potential NULL dereference in meson_drv_bind_master()

From: Neil Armstrong
Date: Tue Mar 20 2018 - 11:04:25 EST


On 20/03/2018 15:20, Wei Yongjun wrote:
> platform_get_resource_byname() 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.
>
> This is detected by Coccinelle semantic patch.
>
> @@
> expression pdev, res, n, t, e, e1, e2;
> @@
>
> res = platform_get_resource_byname(pdev, t, n);
> + if (!res)
> + return -EINVAL;
> ... when != res == NULL
> e = devm_ioremap(e1, res->start, e2);
>
> Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
> ---
> drivers/gpu/drm/meson/meson_drv.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
> index 3baceb7..32b1a6c 100644
> --- a/drivers/gpu/drm/meson/meson_drv.c
> +++ b/drivers/gpu/drm/meson/meson_drv.c
> @@ -197,6 +197,8 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
> priv->io_base = regs;
>
> res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "hhi");
> + if (!res)
> + return -EINVAL;
> /* Simply ioremap since it may be a shared register zone */
> regs = devm_ioremap(dev, res->start, resource_size(res));
> if (!regs) {
> @@ -213,6 +215,8 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
> }
>
> res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dmc");
> + if (!res)
> + return -EINVAL;
> /* Simply ioremap since it may be a shared register zone */
> regs = devm_ioremap(dev, res->start, resource_size(res));
> if (!regs) {
>
>
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>
Thanks,

Acked-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>