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Subject: Re: [PATCH v2] drm/omap: fix possible object reference leak
To:     Wen Yang <wen.yang99@zte.com.cn>, linux-kernel@vger.kernel.org
Cc:     wang.yi59@zte.com.cn, Tomi Valkeinen <tomi.valkeinen@ti.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Sebastian Reichel <sebastian.reichel@collabora.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        dri-devel@lists.freedesktop.org,
        Markus Elfring <Markus.Elfring@web.de>
References: <1554692313-28882-1-git-send-email-wen.yang99@zte.com.cn>
 <1554692313-28882-2-git-send-email-wen.yang99@zte.com.cn>
From:   Mukesh Ojha <mojha@codeaurora.org>
Message-ID: <60d46048-950a-f6f1-0242-bcbfb093b647@codeaurora.org>
Date:   Mon, 8 Apr 2019 14:19:27 +0530
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On 4/8/2019 8:28 AM, Wen Yang wrote:
> The call to of_find_matching_node 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/omapdrm/dss/omapdss-boot-init.c:212:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 209, but without a corresponding object release within this function.
> drivers/gpu/drm/omapdrm/dss/omapdss-boot-init.c:237:1-7: 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>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>

Cheers,
-Mukesh

> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Sebastian Reichel <sebastian.reichel@collabora.com>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-kernel@vger.kernel.org
> Cc: Markus Elfring <Markus.Elfring@web.de>
> ---
> v2->v1: add a jump target.
>
>   drivers/gpu/drm/omapdrm/dss/omapdss-boot-init.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/omapdrm/dss/omapdss-boot-init.c b/drivers/gpu/drm/omapdrm/dss/omapdss-boot-init.c
> index 2b41c75..13b3b4a 100644
> --- a/drivers/gpu/drm/omapdrm/dss/omapdss-boot-init.c
> +++ b/drivers/gpu/drm/omapdrm/dss/omapdss-boot-init.c
> @@ -209,7 +209,7 @@ static int __init omapdss_boot_init(void)
>   	dss = of_find_matching_node(NULL, omapdss_of_match);
>   
>   	if (dss == NULL || !of_device_is_available(dss))
> -		return 0;
> +		goto put_node;
>   
>   	omapdss_walk_device(dss, true);
>   
> @@ -234,6 +234,8 @@ static int __init omapdss_boot_init(void)
>   		kfree(n);
>   	}
>   
> +put_node:
> +	of_node_put(dss);
>   	return 0;
>   }
>