linux-kernel - Re: [PATCH v2 2/3] pmbus_core: Fix NULL pointer dereference

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Date:   Tue, 25 Jul 2023 07:58:48 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Naresh Solanki <naresh.solanki@...ements.com>
Cc:     linux-hwmon@...r.kernel.org, Jean Delvare <jdelvare@...e.com>,
        Patrick Rudolph <patrick.rudolph@...ements.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/3] pmbus_core: Fix NULL pointer dereference

On Tue, Jul 25, 2023 at 02:54:26PM +0200, Naresh Solanki wrote:
> From: Patrick Rudolph <patrick.rudolph@...ements.com>
> 
> Pass i2c_client to _pmbus_is_enabled to drop the assumption
> that a regulator device is passed in.
> 
> This will fix the issue of a NULL pointer dereference when called from
> _pmbus_get_flags.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@...ements.com>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@...ements.com>

Applied.

Thanks,
Guenter

> ---
> Changes in V2:
> - Fix build error.
> ---
>  drivers/hwmon/pmbus/pmbus_core.c | 15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 42fb7286805b..30aeb59062a5 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -2745,9 +2745,8 @@ static const struct pmbus_status_category __maybe_unused pmbus_status_flag_map[]
>  	},
>  };
>  
> -static int _pmbus_is_enabled(struct device *dev, u8 page)
> +static int _pmbus_is_enabled(struct i2c_client *client, u8 page)
>  {
> -	struct i2c_client *client = to_i2c_client(dev->parent);
>  	int ret;
>  
>  	ret = _pmbus_read_byte_data(client, page, PMBUS_OPERATION);
> @@ -2758,14 +2757,13 @@ static int _pmbus_is_enabled(struct device *dev, u8 page)
>  	return !!(ret & PB_OPERATION_CONTROL_ON);
>  }
>  
> -static int __maybe_unused pmbus_is_enabled(struct device *dev, u8 page)
> +static int __maybe_unused pmbus_is_enabled(struct i2c_client *client, u8 page)
>  {
> -	struct i2c_client *client = to_i2c_client(dev->parent);
>  	struct pmbus_data *data = i2c_get_clientdata(client);
>  	int ret;
>  
>  	mutex_lock(&data->update_lock);
> -	ret = _pmbus_is_enabled(dev, page);
> +	ret = _pmbus_is_enabled(client, page);
>  	mutex_unlock(&data->update_lock);
>  
>  	return ret;
> @@ -2844,7 +2842,7 @@ static int _pmbus_get_flags(struct pmbus_data *data, u8 page, unsigned int *flag
>  	if (status < 0)
>  		return status;
>  
> -	if (_pmbus_is_enabled(dev, page)) {
> +	if (_pmbus_is_enabled(client, page)) {
>  		if (status & PB_STATUS_OFF) {
>  			*flags |= REGULATOR_ERROR_FAIL;
>  			*event |= REGULATOR_EVENT_FAIL;
> @@ -2898,7 +2896,10 @@ static int __maybe_unused pmbus_get_flags(struct pmbus_data *data, u8 page, unsi
>  #if IS_ENABLED(CONFIG_REGULATOR)
>  static int pmbus_regulator_is_enabled(struct regulator_dev *rdev)
>  {
> -	return pmbus_is_enabled(rdev_get_dev(rdev), rdev_get_id(rdev));
> +	struct device *dev = rdev_get_dev(rdev);
> +	struct i2c_client *client = to_i2c_client(dev->parent);
> +
> +	return pmbus_is_enabled(client, rdev_get_id(rdev));
>  }
>  
>  static int _pmbus_regulator_on_off(struct regulator_dev *rdev, bool enable)