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From:   Jonas Karlman <jonas@kwiboo.se>
Subject: [PATCH 3/4] drm/rockchip: vop2: Don't crash for invalid
 duplicate_state
Date:   Tue, 20 Jun 2023 06:47:38 +0000 (UTC)
Message-ID: <20230620064732.1525594-4-jonas@kwiboo.se>
In-Reply-To: <20230620064732.1525594-1-jonas@kwiboo.se>
References: <20230620064732.1525594-1-jonas@kwiboo.se>
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To:     Sandy Huang <hjc@rock-chips.com>, Heiko Stuebner <heiko@sntech.de>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Andy Yan <andy.yan@rock-chips.com>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Rob Herring <robh@kernel.org>
Cc:     Mark Yao <markyao0591@gmail.com>, dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org,
        linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
        Jonas Karlman <jonas@kwiboo.se>
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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.

Fixes: 604be85547ce ("drm/rockchip: Add VOP2 driver")
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
---
 drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
index ca73b8ccc29f..f725487d02ef 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
@@ -2099,11 +2099,13 @@ static void vop2_crtc_reset(struct drm_crtc *crtc)
 
 static struct drm_crtc_state *vop2_crtc_duplicate_state(struct drm_crtc *crtc)
 {
-	struct rockchip_crtc_state *vcstate, *old_vcstate;
+	struct rockchip_crtc_state *vcstate;
 
-	old_vcstate = to_rockchip_crtc_state(crtc->state);
+	if (WARN_ON(!crtc->state))
+		return NULL;
 
-	vcstate = kmemdup(old_vcstate, sizeof(*old_vcstate), GFP_KERNEL);
+	vcstate = kmemdup(to_rockchip_crtc_state(crtc->state),
+			  sizeof(*vcstate), GFP_KERNEL);
 	if (!vcstate)
 		return NULL;
 
-- 
2.41.0