[PATCH 1/2] drm/msm/dpu: Add NULL pointer check in dpu_crtc_duplicate_state()

[David Heidelberg via B4 Relay]

From: Petr Hodina <petr.hodina@xxxxxxxxxxxxxx>

dpu_crtc_duplicate_state() assumes that crtc->state is always valid,
but under certain error or teardown paths it may be NULL, leading to
a NULL-pointer dereference when calling to_dpu_crtc_state().

Signed-off-by: Petr Hodina <petr.hodina@xxxxxxxxxxxxxx>
Signed-off-by: David Heidelberg <david@xxxxxxx>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 7 ++++++-
 1 file changed, 6 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 c39f1908ea654..d03666e14d7de 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -1114,7 +1114,12 @@ static void dpu_crtc_reset(struct drm_crtc *crtc)
  */
 static struct drm_crtc_state *dpu_crtc_duplicate_state(struct drm_crtc *crtc)
 {
-	struct dpu_crtc_state *cstate, *old_cstate = to_dpu_crtc_state(crtc->state);
+	struct dpu_crtc_state *cstate, *old_cstate;
+
+	if (WARN_ON(!crtc->state))
+		return NULL;
+
+	old_cstate = to_dpu_crtc_state(crtc->state);
 
 	cstate = kmemdup(old_cstate, sizeof(*old_cstate), GFP_KERNEL);
 	if (!cstate) {

-- 
2.51.0