[PATCH v2] drm/msm/dpu: check dpu_plane_atomic_print_state() for valid sspp

[Abhinav Kumar]

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")
Reported-by: Stephen Boyd <swboyd at chromium.org>
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>
---
Changes in v2:
- move pstate->stage out of the pipe->sspp check
- add reported-by credits for Stephen
- Link to v1: https://lore.kernel.org/r/20241209-check-state-before-dump-v1-1-7a9d8bc6048f@quicinc.com
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 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..703e58901d53f26eba69566c2784655015c6a584 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
@@ -1335,12 +1335,15 @@ static void dpu_plane_atomic_print_state(struct drm_printer *p,
 
 	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, "\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>