linux-kernel - Re: [PATCH v2] platform/x86: int3472: Fix double free of GPIO device during unregister

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Message-ID: <37667f90-7333-4316-8858-8445f8f81409@kernel.org>
Date: Tue, 28 Oct 2025 10:34:47 +0100
From: Hans de Goede <hansg@...nel.org>
To: Qiu Wenbo <qiuwenbo@...me.org>, Daniel Scally <djrscally@...il.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
 Andy Shevchenko <andy@...nel.org>,
 Sakari Ailus <sakari.ailus@...ux.intel.com>,
 platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] platform/x86: int3472: Fix double free of GPIO device
 during unregister

Hi,

On 28-Oct-25 7:30 AM, Qiu Wenbo wrote:
> From: Qiu Wenbo <qiuwenbo@...insec.com.cn>
> 
> regulator_unregister() already frees the associated GPIO device. On
> ThinkPad X9 (Lunar Lake), this causes a double free issue that leads to
> random failures when other drivers (typically Intel THC) attempt to
> allocate interrupts. The root cause is that the reference count of the
> pinctrl_intel_platform module unexpectedly drops to zero when this
> driver defers its probe.
> 
> This behavior can also be reproduced by unloading the module directly.
> 
> Fix the issue by removing the redundant release of the GPIO device
> during regulator unregistration.
> 
> Cc: stable@...r.kernel.org
> Fixes: 1e5d088a52c2 ("platform/x86: int3472: Stop using devm_gpiod_get()")
> Signed-off-by: Qiu Wenbo <qiuwenbo@...insec.com.cn>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@...el.com>
> Reviewed-by: Sakari Ailus <sakari.ailus@...ux.intel.com>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hansg@...nel.org>

Regards,

Hans



> ---
> Changes since V1:
>  - Add Reviewed-by: from Andy Shevchenko and Sakari Ailus
>  - Add Cc to stable@
>  - Remove the blank line after Fixes:
> 
>  drivers/platform/x86/intel/int3472/clk_and_regulator.c | 5 +----
>  include/linux/platform_data/x86/int3472.h              | 1 -
>  2 files changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/int3472/clk_and_regulator.c b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
> index 476ec24d37020..9e052b164a1ab 100644
> --- a/drivers/platform/x86/intel/int3472/clk_and_regulator.c
> +++ b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
> @@ -245,15 +245,12 @@ int skl_int3472_register_regulator(struct int3472_discrete_device *int3472,
>  	if (IS_ERR(regulator->rdev))
>  		return PTR_ERR(regulator->rdev);
>  
> -	int3472->regulators[int3472->n_regulator_gpios].ena_gpio = gpio;
>  	int3472->n_regulator_gpios++;
>  	return 0;
>  }
>  
>  void skl_int3472_unregister_regulator(struct int3472_discrete_device *int3472)
>  {
> -	for (int i = 0; i < int3472->n_regulator_gpios; i++) {
> +	for (int i = 0; i < int3472->n_regulator_gpios; i++)
>  		regulator_unregister(int3472->regulators[i].rdev);
> -		gpiod_put(int3472->regulators[i].ena_gpio);
> -	}
>  }
> diff --git a/include/linux/platform_data/x86/int3472.h b/include/linux/platform_data/x86/int3472.h
> index 1571e9157fa50..b1b837583d544 100644
> --- a/include/linux/platform_data/x86/int3472.h
> +++ b/include/linux/platform_data/x86/int3472.h
> @@ -100,7 +100,6 @@ struct int3472_gpio_regulator {
>  	struct regulator_consumer_supply supply_map[GPIO_REGULATOR_SUPPLY_MAP_COUNT * 2];
>  	char supply_name_upper[GPIO_SUPPLY_NAME_LENGTH];
>  	char regulator_name[GPIO_REGULATOR_NAME_LENGTH];
> -	struct gpio_desc *ena_gpio;
>  	struct regulator_dev *rdev;
>  	struct regulator_desc rdesc;
>  };