Re: [PATCH 6/7] mfd: max8997: Fix possible NULL pointer dereference on i2c_new_dummy error

[Lee Jones]

On Tue, 11 Feb 2014, Krzysztof Kozlowski wrote:

> During probe the driver allocates dummy I2C devices for RTC, haptic and
> MUIC 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, haptic or MUIC devices, fail also the
> probe for main MFD driver.
> 
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
>  drivers/mfd/max8997.c |   18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/drivers/mfd/max8997.c b/drivers/mfd/max8997.c
> index be88a3bf7b85..3ffc11dfc3b6 100644
> --- a/drivers/mfd/max8997.c
> +++ b/drivers/mfd/max8997.c
> @@ -208,10 +208,26 @@ static int max8997_i2c_probe(struct i2c_client *i2c,
>  	mutex_init(&max8997->iolock);
>  
>  	max8997->rtc = i2c_new_dummy(i2c->adapter, I2C_ADDR_RTC);
> +	if (!max8997->rtc) {
> +		dev_err(max8997->dev, "Failed to allocate I2C device for RTC\n");
> +		return -ENODEV;
> +	}
>  	i2c_set_clientdata(max8997->rtc, max8997);
> +
>  	max8997->haptic = i2c_new_dummy(i2c->adapter, I2C_ADDR_HAPTIC);
> +	if (!max8997->haptic) {
> +		dev_err(max8997->dev, "Failed to allocate I2C device for Haptic\n");
> +		ret = -ENODEV;
> +		goto err_i2c_haptic;
> +	}
>  	i2c_set_clientdata(max8997->haptic, max8997);
> +
>  	max8997->muic = i2c_new_dummy(i2c->adapter, I2C_ADDR_MUIC);
> +	if (!max8997->muic) {
> +		dev_err(max8997->dev, "Failed to allocate I2C device for MUIC\n");
> +		ret = -ENODEV;
> +		goto err_i2c_muic;
> +	}
>  	i2c_set_clientdata(max8997->muic, max8997);
>  
>  	pm_runtime_set_active(max8997->dev);
> @@ -239,7 +255,9 @@ static int max8997_i2c_probe(struct i2c_client *i2c,
>  err_mfd:
>  	mfd_remove_devices(max8997->dev);
>  	i2c_unregister_device(max8997->muic);
> +err_i2c_muic:
>  	i2c_unregister_device(max8997->haptic);
> +err_i2c_haptic:
>  	i2c_unregister_device(max8997->rtc);
>  	return ret;
>  }

Applied, thanks.

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