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Date:   Fri, 11 Aug 2023 12:12:26 +0300
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Bartosz Golaszewski <brgl@bgdev.pl>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Kent Gibson <warthog618@gmail.com>, linux-gpio@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Subject: Re: [PATCH v2] gpiolib: fix reference leaks when removing GPIO chips
 still in use
Message-ID: <ZNX7etYJrCuERn8/@smile.fi.intel.com>
References: <20230810184846.22144-1-brgl@bgdev.pl>
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On Thu, Aug 10, 2023 at 08:48:46PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> After we remove a GPIO chip that still has some requested descriptors,
> gpiod_free_commit() will fail and we will never put the references to the
> GPIO device and the owning module in gpiod_free().
> 
> Rework this function to:
> - not warn on desc == NULL as this is a use-case on which most free
>   functions silently return
> - put the references to desc->gdev and desc->gdev->owner unconditionally
>   so that the release callback actually gets called when the remaining
>   references are dropped by external GPIO users

...

> +	/*
> +	 * We must not use VALIDATE_DESC_VOID() as the underlying gdev->chip
> +	 * may already be NULL but we still want to put the references.
> +	 */

Clear now!

...

> +	if (!gpiod_free_commit(desc))
>  		WARN_ON(extra_checks);

	/* Always call gpiod_free_commit() */
	WARN_ON(!gpiod_free_commit(desc) && extra_checks);

?

-- 
With Best Regards,
Andy Shevchenko