[PATCH] drm/msm/dpu: Add check for cstate

[Jiasheng Jiang]

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 at iscas.ac.cn>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index 13ce321283ff..22c2787b7b38 100644
--- 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);
 }
 
 /**
-- 
2.25.1