[PATCH] drm/msm/dpu: check dpu_plane_atomic_print_state() for valid sspp

[Dmitry Baryshkov]

On Mon, Dec 09, 2024 at 12:37:51PM -0800, Abhinav Kumar wrote:
> Similar to the r_pipe sspp protect, add a check to protect
> the pipe state prints to avoid NULL ptr dereference for cases when
> the state is dumped without a corresponding atomic_check() where the
> pipe->sspp is assigned.
> 
> Fixes: 31f7148fd370 ("drm/msm/dpu: move pstate->pipe initialization to dpu_plane_atomic_check")
> Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/67
> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
> ---
> To: Rob Clark <robdclark at gmail.com>
> To: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> To: Sean Paul <sean at poorly.run>
> To: Marijn Suijten <marijn.suijten at somainline.org>
> To: David Airlie <airlied at gmail.com>
> To: Simona Vetter <simona at ffwll.ch>
> Cc: linux-arm-msm at vger.kernel.org
> Cc: dri-devel at lists.freedesktop.org
> Cc: freedreno at lists.freedesktop.org
> Cc: linux-kernel at vger.kernel.org
> Cc: Stephen Boyd <swboyd at chromium.org>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> index 3ffac24333a2a5b01135d4ece418432d4a74dc04..fe3fd9587ec61f241ccb8c28925c7902b92bcdcd 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
> @@ -1333,14 +1333,17 @@ static void dpu_plane_atomic_print_state(struct drm_printer *p,
>  	const struct dpu_sw_pipe *r_pipe = &pstate->r_pipe;
>  	const struct dpu_sw_pipe_cfg *r_pipe_cfg = &pstate->r_pipe_cfg;
>  
> -	drm_printf(p, "\tstage=%d\n", pstate->stage);
> -
> -	drm_printf(p, "\tsspp[0]=%s\n", pipe->sspp->cap->name);
> -	drm_printf(p, "\tmultirect_mode[0]=%s\n", dpu_get_multirect_mode(pipe->multirect_mode));
> -	drm_printf(p, "\tmultirect_index[0]=%s\n",
> -		   dpu_get_multirect_index(pipe->multirect_index));
> -	drm_printf(p, "\tsrc[0]=" DRM_RECT_FMT "\n", DRM_RECT_ARG(&pipe_cfg->src_rect));
> -	drm_printf(p, "\tdst[0]=" DRM_RECT_FMT "\n", DRM_RECT_ARG(&pipe_cfg->dst_rect));
> +	if (pipe->sspp) {
> +		drm_printf(p, "\tstage=%d\n", pstate->stage);

Please keep pstate->stage out of the if() statement. LGTM otherwise.

> +
> +		drm_printf(p, "\tsspp[0]=%s\n", pipe->sspp->cap->name);
> +		drm_printf(p, "\tmultirect_mode[0]=%s\n",
> +			   dpu_get_multirect_mode(pipe->multirect_mode));
> +		drm_printf(p, "\tmultirect_index[0]=%s\n",
> +			   dpu_get_multirect_index(pipe->multirect_index));
> +		drm_printf(p, "\tsrc[0]=" DRM_RECT_FMT "\n", DRM_RECT_ARG(&pipe_cfg->src_rect));
> +		drm_printf(p, "\tdst[0]=" DRM_RECT_FMT "\n", DRM_RECT_ARG(&pipe_cfg->dst_rect));
> +	}
>  
>  	if (r_pipe->sspp) {
>  		drm_printf(p, "\tsspp[1]=%s\n", r_pipe->sspp->cap->name);
> 
> ---
> base-commit: 9d6a414ad31e8eb296cd6f2c1834b2c6994960a0
> change-id: 20241209-check-state-before-dump-2a015ace5f49
> 
> Best regards,
> -- 
> Abhinav Kumar <quic_abhinavk at quicinc.com>
> 

-- 
With best wishes
Dmitry