linux-kernel - Re: [PATCH 2/3] drm/bridge: imx8qxp-pxl2dpi: Fix NULL pointer dereference in imx8qxp_pxl2dpi_bridge

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Message-ID: <aXOMIJCuLoLrq8BC@lizhi-Precision-Tower-5810>
Date: Fri, 23 Jan 2026 09:56:32 -0500
From: Frank Li <Frank.li@....com>
To: Liu Ying <victor.liu@....com>
Cc: Andrzej Hajda <andrzej.hajda@...el.com>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Robert Foss <rfoss@...nel.org>,
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
	Jonas Karlman <jonas@...boo.se>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	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>,
	Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>,
	Luca Ceresoli <luca.ceresoli@...tlin.com>,
	dri-devel@...ts.freedesktop.org, imx@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] drm/bridge: imx8qxp-pxl2dpi: Fix NULL pointer
 dereference in imx8qxp_pxl2dpi_bridge_destroy()

On Fri, Jan 23, 2026 at 05:22:16PM +0800, Liu Ying wrote:
> Pointer bridge->driver_private in imx8qxp_pxl2dpi_bridge_destroy()
> is NULL when imx8qxp_pxl2dpi_bridge_probe() returns error, because
> the pointer is initialized only when imx8qxp_pxl2dpi_bridge_probe()
> returns 0.  The NULL pointer would be set to pointer p2d and then
> NULL pointer p2d would be dereferenced.  Fix this by returning early
> from imx8qxp_pxl2dpi_bridge_destroy() if !p2d is true.
>
> Fixes: 900699ba830f ("drm/bridge: imx8qxp-pxl2dpi: get/put the companion bridge")
> Signed-off-by: Liu Ying <victor.liu@....com>
> ---

Reviewed-by: Frank Li <Frank.Li@....com>

>  drivers/gpu/drm/bridge/imx/imx8qxp-pxl2dpi.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/imx/imx8qxp-pxl2dpi.c b/drivers/gpu/drm/bridge/imx/imx8qxp-pxl2dpi.c
> index f0814702b641..9dc2b3d2ecef 100644
> --- a/drivers/gpu/drm/bridge/imx/imx8qxp-pxl2dpi.c
> +++ b/drivers/gpu/drm/bridge/imx/imx8qxp-pxl2dpi.c
> @@ -67,6 +67,9 @@ static void imx8qxp_pxl2dpi_bridge_destroy(struct drm_bridge *bridge)
>  {
>  	struct imx8qxp_pxl2dpi *p2d = bridge->driver_private;
>
> +	if (!p2d)
> +		return;
> +
>  	drm_bridge_put(p2d->companion);
>  }
>
>
> --
> 2.43.0
>