Re: [PATCH v1 1/1] drm/mediatek: Fix wrong check of nvmem_cell_read

[AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>]

Il 25/09/24 10:40, Liankun Yang ha scritto:
> If the len is 0, kernel crash will occur when performing operations.
> Add the len check conditions to prevent kernel crash.
> 

Please fix the commit title:

drm/mediatek: mtk_dp: Fix potential KP on 0 bytes nvmem cell read

> Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver")
> 

Please remove this blank line between the Fixes tag and your S-o-b.

> Signed-off-by: Liankun Yang <liankun.yang@mediatek.com>
> ---
>   drivers/gpu/drm/mediatek/mtk_dp.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
> index d8796a904eca..0cc75ba96b98 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> @@ -1082,7 +1082,7 @@ static void mtk_dp_get_calibration_data(struct mtk_dp *mtk_dp)
>   	buf = (u32 *)nvmem_cell_read(cell, &len);
>   	nvmem_cell_put(cell);
>   
> -	if (IS_ERR(buf) || ((len / sizeof(u32)) != 4)) {
> +	if (IS_ERR(buf) || (len == 0) || ((len / sizeof(u32)) != 4)) {

if (IS_ERR(buf) || !len || ((len / sizeof(u32)) != 4)) {

Cheers,
Angelo