linux-kernel - Re: [PATCH] drm/bridge: samsung-dsim: Fix potential double-free in TE GPIO handling

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Message-ID: <e0121a48-1a69-453b-b58b-8e282956165b@samsung.com>
Date: Mon, 4 Aug 2025 14:29:43 +0200
From: Marek Szyprowski <m.szyprowski@...sung.com>
To: Miaoqian Lin <linmq006@...il.com>, Inki Dae <inki.dae@...sung.com>,
	Jagan Teki <jagan@...rulasolutions.com>, 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>, Marek Vasut <marex@...x.de>,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/bridge: samsung-dsim: Fix potential double-free in
 TE GPIO handling

On 04.08.2025 14:24, Miaoqian Lin wrote:
> The devm_gpiod_get_optional() function uses device-managed resources that
> are automatically cleaned up. The
> gpiod_put() calls in both the error path of samsung_dsim_register_te_irq()
> and in samsung_dsim_unregister_te_irq() are redundant and may lead to
> double-free when the device is removed.
>
> Fixes: e7447128ca4a ("drm: bridge: Generalize Exynos-DSI driver into a Samsung DSIM bridge")
> Signed-off-by: Miaoqian Lin <linmq006@...il.com>
Reviewed-by: Marek Szyprowski <m.szyprowski@...sung.com>
> ---
>   drivers/gpu/drm/bridge/samsung-dsim.c | 5 +----
>   1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
> index bccc88d25948..6ffaee6b7738 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -1691,7 +1691,6 @@ static int samsung_dsim_register_te_irq(struct samsung_dsim *dsi, struct device
>   				   IRQF_TRIGGER_RISING | IRQF_NO_AUTOEN, "TE", dsi);
>   	if (ret) {
>   		dev_err(dsi->dev, "request interrupt failed with %d\n", ret);
> -		gpiod_put(dsi->te_gpio);
>   		return ret;
>   	}
>   
> @@ -1790,10 +1789,8 @@ static int samsung_dsim_host_attach(struct mipi_dsi_host *host,
>   
>   static void samsung_dsim_unregister_te_irq(struct samsung_dsim *dsi)
>   {
> -	if (dsi->te_gpio) {
> +	if (dsi->te_gpio)
>   		free_irq(gpiod_to_irq(dsi->te_gpio), dsi);
> -		gpiod_put(dsi->te_gpio);
> -	}
>   }
>   
>   static int samsung_dsim_host_detach(struct mipi_dsi_host *host,

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland