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Date:   Wed, 21 Jun 2023 10:06:12 +0200
From:   Sascha Hauer <s.hauer@pengutronix.de>
To:     Jonas Karlman <jonas@kwiboo.se>
Cc:     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>,
        Rob Herring <robh@kernel.org>,
        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
Subject: Re: [PATCH 3/4] drm/rockchip: vop2: Don't crash for invalid
 duplicate_state
Message-ID: <20230621080612.GX18491@pengutronix.de>
References: <20230620064732.1525594-1-jonas@kwiboo.se>
 <20230620064732.1525594-4-jonas@kwiboo.se>
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On Tue, Jun 20, 2023 at 06:47:38AM +0000, Jonas Karlman wrote:
> 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>

Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>

Sascha

> ---
>  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
> 
> 

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