drm/msm/dpu: Add check for cstate

As kzalloc may fail and return NULL pointer,
it should be better to check cstate
in order to avoid the NULL pointer dereference
in __drm_atomic_helper_crtc_reset.

Fixes: 1cff7440a86e ("drm/msm: Convert to using __drm_atomic_helper_crtc_reset() for reset.")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/514163/
Link: https://lore.kernel.org/r/20221206080517.43786-1-jiasheng@iscas.ac.cn
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index 4181903..175d255 100644 (file)
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -968,7 +968,10 @@ static void dpu_crtc_reset(struct drm_crtc *crtc)
        if (crtc->state)
                dpu_crtc_destroy_state(crtc, crtc->state);
 
-       __drm_atomic_helper_crtc_reset(crtc, &cstate->base);
+       if (cstate)
+               __drm_atomic_helper_crtc_reset(crtc, &cstate->base);
+       else
+               __drm_atomic_helper_crtc_reset(crtc, NULL);
 }
 
 /**