Re: [PATCH 5/7] mfd: max8925: Fix possible NULL pointer dereference on i2c_new_dummy error

[Lee Jones <lee.jones@linaro.org>]

On Tue, 11 Feb 2014, Krzysztof Kozlowski wrote:

> During probe the driver allocates dummy I2C devices for RTC and ADC
> with i2c_new_dummy() but it does not check the return value of this
> calls.
> 
> In case of error (i2c_new_device(): memory allocation failure or I2C
> address cannot be used) this function returns NULL which is later used
> by i2c_unregister_device().
> 
> If i2c_new_dummy() fails for RTC or ADC devices, fail also the probe
> for main MFD driver.
> 
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/mfd/max8925-i2c.c |    9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/mfd/max8925-i2c.c b/drivers/mfd/max8925-i2c.c
> index 176aa26fc787..a83eed5c15ca 100644
> --- a/drivers/mfd/max8925-i2c.c
> +++ b/drivers/mfd/max8925-i2c.c
> @@ -181,9 +181,18 @@ static int max8925_probe(struct i2c_client *client,
>  	mutex_init(&chip->io_lock);
>  
>  	chip->rtc = i2c_new_dummy(chip->i2c->adapter, RTC_I2C_ADDR);
> +	if (!chip->rtc) {
> +		dev_err(chip->dev, "Failed to allocate I2C device for RTC\n");
> +		return -ENODEV;
> +	}
>  	i2c_set_clientdata(chip->rtc, chip);
>  
>  	chip->adc = i2c_new_dummy(chip->i2c->adapter, ADC_I2C_ADDR);
> +	if (!chip->adc) {
> +		dev_err(chip->dev, "Failed to allocate I2C device for ADC\n");
> +		i2c_unregister_device(chip->rtc);
> +		return -ENODEV;
> +	}
>  	i2c_set_clientdata(chip->adc, chip);
>  
>  	device_init_wakeup(&client->dev, 1);

Applied, thanks.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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