Re: [PATCH 2/2] drm/amd/display: Fix null check for pipe_ctx->plane_state in hwss_setup_dpp

["Chung, ChiaHsuan (Tom)" <chiahsuan.chung@amd.com>]

Reviewed-by: Tom Chung <chiahsuan.chung@amd.com>

On 11/5/2024 10:01 PM, Zicheng Qu wrote:
> This commit addresses a null pointer dereference issue in
> hwss_setup_dpp(). The issue could occur when pipe_ctx->plane_state is
> null. The fix adds a check to ensure `pipe_ctx->plane_state` is not null
> before accessing. This prevents a null pointer dereference.
>
> Fixes: 0baae6246307 ("drm/amd/display: Refactor fast update to use new HWSS build sequence")
> Signed-off-by: Zicheng Qu <quzicheng@huawei.com>
> ---
>   drivers/gpu/drm/amd/display/dc/core/dc_hw_sequencer.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/core/dc_hw_sequencer.c
> index 7ee2be8f82c4..bb766c2a7417 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc_hw_sequencer.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_hw_sequencer.c
> @@ -881,6 +881,9 @@ void hwss_setup_dpp(union block_sequence_params *params)
>   	struct dpp *dpp = pipe_ctx->plane_res.dpp;
>   	struct dc_plane_state *plane_state = pipe_ctx->plane_state;
>   
> +	if (!plane_state)
> +		return;
> +
>   	if (dpp && dpp->funcs->dpp_setup) {
>   		// program the input csc
>   		dpp->funcs->dpp_setup(dpp,