Re: [PATCH v2 5/7] regulator: plug of_node leak in regulator_register()'s error path

[Vladimir Zapolskiy]

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: sta...@vger.kernel.org
> Fixes: 9177514ce349 ("regulator: fix memory leak on error path of 
> regulator_register()")
> Signed-off-by: Michał Mirosław <mirq-li...@rere.qmqm.pl>
> Acked-by: Vladimir Zapolskiy <v...@mleia.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