Re: [PATCH 4/7] mfd: max77693: 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 MUIC and haptic
> 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 devm_regmap_init_i2c() and i2c_unregister_device().
> 
> If i2c_new_dummy() fails for MUIC or haptic 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/max77693.c |   12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/max77693.c b/drivers/mfd/max77693.c
> index e0859987ab6b..c5535f018466 100644
> --- a/drivers/mfd/max77693.c
> +++ b/drivers/mfd/max77693.c
> @@ -148,9 +148,18 @@ static int max77693_i2c_probe(struct i2c_client *i2c,
>  		dev_info(max77693->dev, "device ID: 0x%x\n", reg_data);
>  
>  	max77693->muic = i2c_new_dummy(i2c->adapter, I2C_ADDR_MUIC);
> +	if (!max77693->muic) {
> +		dev_err(max77693->dev, "Failed to allocate I2C device for MUIC\n");
> +		return -ENODEV;
> +	}
>  	i2c_set_clientdata(max77693->muic, max77693);
>  
>  	max77693->haptic = i2c_new_dummy(i2c->adapter, I2C_ADDR_HAPTIC);
> +	if (!max77693->haptic) {
> +		dev_err(max77693->dev, "Failed to allocate I2C device for Haptic\n");
> +		ret = -ENODEV;
> +		goto err_i2c_haptic;
> +	}
>  	i2c_set_clientdata(max77693->haptic, max77693);
>  
>  	/*
> @@ -184,8 +193,9 @@ err_mfd:
>  	max77693_irq_exit(max77693);
>  err_irq:
>  err_regmap_muic:
> -	i2c_unregister_device(max77693->muic);
>  	i2c_unregister_device(max77693->haptic);
> +err_i2c_haptic:
> +	i2c_unregister_device(max77693->muic);
>  	return ret;
>  }
>  

Applied, thanks.

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