linux-kernel - Re: [PATCH] drm/logicvc: Fix device node reference leak in logicvc_drm_config

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Message-ID: <20260203105747.71b71dfa@kmaincent-XPS-13-7390>
Date: Tue, 3 Feb 2026 10:57:47 +0100
From: Kory Maincent <kory.maincent@...tlin.com>
To: Felix Gu <ustc.gu@...il.com>
Cc: Paul Kocialkowski <paulk@...-base.io>, Maarten Lankhorst
 <maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>,
 Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>,
 Simona Vetter <simona@...ll.ch>, Paul Kocialkowski
 <paul.kocialkowski@...tlin.com>, dri-devel@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/logicvc: Fix device node reference leak in
 logicvc_drm_config_parse()

On Fri, 30 Jan 2026 00:21:19 +0800
Felix Gu <ustc.gu@...il.com> wrote:

> The logicvc_drm_config_parse() function calls of_get_child_by_name() to
> find the "layers" node but fails to release the reference, leading to a
> device node reference leak.
> 
> Fix this by using the __free(device_node) cleanup attribute to automatic
> release the reference when the variable goes out of scope.
> 
> Fixes: efeeaefe9be5 ("drm: Add support for the LogiCVC display controller")
> Signed-off-by: Felix Gu <ustc.gu@...il.com>
> ---
>  drivers/gpu/drm/logicvc/logicvc_drm.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/logicvc/logicvc_drm.c
> b/drivers/gpu/drm/logicvc/logicvc_drm.c index 204b0fee55d0..bbebf4fc7f51
> 100644 --- a/drivers/gpu/drm/logicvc/logicvc_drm.c
> +++ b/drivers/gpu/drm/logicvc/logicvc_drm.c
> @@ -92,7 +92,6 @@ static int logicvc_drm_config_parse(struct logicvc_drm
> *logicvc) struct device *dev = drm_dev->dev;
>  	struct device_node *of_node = dev->of_node;
>  	struct logicvc_drm_config *config = &logicvc->config;
> -	struct device_node *layers_node;
>  	int ret;
>  
>  	logicvc_of_property_parse_bool(of_node,
> LOGICVC_OF_PROPERTY_DITHERING, @@ -128,7 +127,8 @@ static int
> logicvc_drm_config_parse(struct logicvc_drm *logicvc) if (ret)
>  		return ret;
>  
> -	layers_node = of_get_child_by_name(of_node, "layers");
> +	struct device_node *layers_node __free(device_node) =
> +		of_get_child_by_name(of_node, "layers");

We usualy don't declare variable in the middle of a function.
You should rather simply change the declaration line at the top like this:
struct device_node *layers_node __free(device_node) = NULL;

Regards,
-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com