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Date:   Thu, 4 Apr 2019 16:35:24 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Wen Yang <wen.yang99@zte.com.cn>
Cc:     linux-kernel@vger.kernel.org, wang.yi59@zte.com.cn,
        Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        dri-devel@lists.freedesktop.org, linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH 6/7] drm: rcar-du: fix possible object reference leak
Message-ID: <20190404133524.GC7817@pendragon.ideasonboard.com>
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 <1554307455-40361-7-git-send-email-wen.yang99@zte.com.cn>
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Hi Wen,

Thank you for the patch.

On Thu, Apr 04, 2019 at 12:04:14AM +0800, Wen Yang wrote:
> The call to of_get_parent returns a node pointer with refcount
> incremented thus it must be explicitly decremented after the last
> usage.
> 
> Detected by coccinelle with the following warnings:
> drivers/gpu/drm/rcar-du/rcar_du_of.c:235:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 216, but without a corresponding object release within this function.
> drivers/gpu/drm/rcar-du/rcar_du_of.c:236:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 209, but without a corresponding object release within this function.
> 
> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-renesas-soc@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org (open list)
> ---
>  drivers/gpu/drm/rcar-du/rcar_du_of.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_of.c b/drivers/gpu/drm/rcar-du/rcar_du_of.c
> index afef696..30bceca 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_of.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_of.c
> @@ -232,6 +232,8 @@ static void __init rcar_du_of_lvds_patch(const struct of_device_id *of_ids)
>  	lvds_node = of_find_compatible_node(NULL, NULL, compatible);
>  	if (lvds_node) {
>  		of_node_put(lvds_node);
> +		of_node_put(soc_node);
> +		of_node_put(du_node);
>  		return;

Wouldn't it be simpler to just turn the return into a goto done ?

>  	}
>  

-- 
Regards,

Laurent Pinchart