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

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Message-ID: <aQCUu5vCPlglC0Kd@smile.fi.intel.com>
Date: Tue, 28 Oct 2025 12:02:35 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Dan Scally <dan.scally@...asonboard.com>
Cc: Qiu Wenbo <qiuwenbo@...me.org>, Daniel Scally <djrscally@...il.com>,
	Hans de Goede <hansg@...nel.org>,
	Qiu Wenbo <qiuwenbo@...insec.com.cn>,
	platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
	Sakari Ailus <sakari.ailus@...ux.intel.com>,
	Andy Shevchenko <andy@...nel.org>
Subject: Re: [PATCH] platform/x86: int3472: Fix double free of GPIO device
 during unregister

On Tue, Oct 28, 2025 at 08:55:07AM +0000, Dan Scally wrote:
> On 24/10/2025 06:05, Qiu Wenbo wrote:
> > 
> > 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.
> > 
> > Fixes: 1e5d088a52c2 ("platform/x86: int3472: Stop using devm_gpiod_get()")

> However the Fixes tag I wonder about; devm_gpiod_get() will also result in a
> call to gpiod_put() when the module is unloaded; doesn't that mean that the
> same issue  will occur before that commit?

Actually a good question! To me sounds like it's a bug(?) in regulator code.
It must not release resources it didn't acquire. This sounds like a clear
layering violation.

-- 
With Best Regards,
Andy Shevchenko