<html><body><p>
<pre>
Hi, Angelo:
On Tue, 2024-11-12 at 11:50 +0100, AngeloGioacchino Del Regno wrote:
> External email : Please do not click links or open attachments until you have verified the sender or the content.
>
>
> The struct device_node *next pointer is not initialized, and it is
> used in an error path in which it may have never been modified by
> function mtk_drm_of_get_ddp_ep_cid().
>
> Since the error path is relying on that pointer being NULL for the
> OVL Adaptor and/or invalid component check and since said pointer
> is being used in prints for %pOF, in the case that it points to a
> bogus address, the print may cause a KP.
>
> To resolve that, initialize the *next pointer to NULL before usage.
Reviewed-by: CK Hu <ck.hu@mediatek.com>
>
> Fixes: 4c932840db1d ("drm/mediatek: Implement OF graphs support for display paths")
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
> drivers/gpu/drm/mediatek/mtk_drm_drv.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index 9a8ef8558da9..bc06c664e80f 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -900,7 +900,7 @@ static int mtk_drm_of_ddp_path_build_one(struct device *dev, enum mtk_crtc_path
> const unsigned int **out_path,
> unsigned int *out_path_len)
> {
> - struct device_node *next, *prev, *vdo = dev->parent->of_node;
> + struct device_node *next = NULL, *prev, *vdo = dev->parent->of_node;
> unsigned int temp_path[DDP_COMPONENT_DRM_ID_MAX] = { 0 };
> unsigned int *final_ddp_path;
> unsigned short int idx = 0;
> --
> 2.47.0
>
</pre>
</p></body></html><!--type:text--><!--{--><pre>************* MEDIATEK Confidentiality Notice ********************
The information contained in this e-mail message (including any
attachments) may be confidential, proprietary, privileged, or otherwise
exempt from disclosure under applicable laws. It is intended to be
conveyed only to the designated recipient(s). Any use, dissemination,
distribution, printing, retaining or copying of this e-mail (including its
attachments) by unintended recipient(s) is strictly prohibited and may
be unlawful. If you are not an intended recipient of this e-mail, or believe
that you have received this e-mail in error, please notify the sender
immediately (by replying to this e-mail), delete any and all copies of
this e-mail (including any attachments) from your system, and do not
disclose the content of this e-mail to any other person. Thank you!
</pre><!--}-->