[PATCH] drm/rockchip: vop: Don't crash for invalid duplicate_state()

[Brian Norris]

It's possible for users to try to duplicate the CRTC state even when the
state doesn't exist. drm_atomic_helper_crtc_duplicate_state() (and other
users of __drm_atomic_helper_crtc_duplicate_state()) already guard this
with a WARN_ON() instead of crashing, so let's do that here too.

Signed-off-by: Brian Norris <briannorris at chromium.org>
---

 drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index 74562d40f639..daf192881353 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -1570,6 +1570,9 @@ static struct drm_crtc_state *vop_crtc_duplicate_state(struct drm_crtc *crtc)
 {
 	struct rockchip_crtc_state *rockchip_state;
 
+	if (WARN_ON(!crtc->state))
+		return NULL;
+
 	rockchip_state = kzalloc(sizeof(*rockchip_state), GFP_KERNEL);
 	if (!rockchip_state)
 		return NULL;
-- 
2.36.1.476.g0c4daa206d-goog