linux-kernel - Re: [PATCH v2 5/7] regulator: plug of_node leak in regulator

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Message-ID: <cddd3d73-8666-d64b-34f5-d82a3b31cf36@mleia.com>
Date:   Wed, 12 Aug 2020 09:29:12 +0300
From:   Vladimir Zapolskiy <vz@...ia.com>
To:     Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        Dmitry Osipenko <digetx@...il.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 5/7] regulator: plug of_node leak in
 regulator_register()'s error path

Hi Michał,

On 8/12/20 4:31 AM, Michał Mirosław wrote:
> By calling device_initialize() earlier and noting that kfree(NULL) is
> ok, we can save a bit of code in error handling and plug of_node leak.
> Fixed commit already did part of the work.
> 
> Cc: stable@...r.kernel.org
> Fixes: 9177514ce349 ("regulator: fix memory leak on error path of regulator_register()")
> Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
> Acked-by: Vladimir Zapolskiy <vz@...ia.com>
> ---
>  drivers/regulator/core.c | 13 ++++---------
>  1 file changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> index 71749f48caee..448a267641df 100644
> --- a/drivers/regulator/core.c
> +++ b/drivers/regulator/core.c
> @@ -5137,6 +5137,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
>  		ret = -ENOMEM;
>  		goto rinse;
>  	}
> +	device_initialize(&rdev->dev);
>  
>  	/*
>  	 * Duplicate the config so the driver could override it after
> @@ -5144,9 +5145,8 @@ regulator_register(const struct regulator_desc *regulator_desc,
>  	 */
>  	config = kmemdup(cfg, sizeof(*cfg), GFP_KERNEL);
>  	if (config == NULL) {
> -		kfree(rdev);
>  		ret = -ENOMEM;
> -		goto rinse;
> +		goto clean;

Here config == NULL

>  	}
>  
>  	init_data = regulator_of_get_init_data(dev, regulator_desc, config,
> @@ -5158,10 +5158,8 @@ regulator_register(const struct regulator_desc *regulator_desc,
>  	 * from a gpio extender or something else.
>  	 */
>  	if (PTR_ERR(init_data) == -EPROBE_DEFER) {
> -		kfree(config);
> -		kfree(rdev);
>  		ret = -EPROBE_DEFER;
> -		goto rinse;
> +		goto clean;
>  	}
>  
>  	/*
> @@ -5214,7 +5212,6 @@ regulator_register(const struct regulator_desc *regulator_desc,
>  	}
>  
>  	/* register with sysfs */
> -	device_initialize(&rdev->dev);
>  	rdev->dev.class = &regulator_class;
>  	rdev->dev.parent = dev;
>  	dev_set_name(&rdev->dev, "regulator.%lu",
> @@ -5292,13 +5289,11 @@ regulator_register(const struct regulator_desc *regulator_desc,
>  	mutex_lock(&regulator_list_mutex);
>  	regulator_ena_gpio_free(rdev);
>  	mutex_unlock(&regulator_list_mutex);
> -	put_device(&rdev->dev);
> -	rdev = NULL;
>  clean:
>  	if (dangling_of_gpiod)
>  		gpiod_put(config->ena_gpiod);

And above 'config' NULL pointer could be dereferenced now, right?

> -	kfree(rdev);
>  	kfree(config);
> +	put_device(&rdev->dev);
>  rinse:
>  	if (dangling_cfg_gpiod)
>  		gpiod_put(cfg->ena_gpiod);
> 

--
Best wishes,
Vladimir