Re: [PATCH] iio: mcp320x: Fix NULL pointer dereference

[Jonathan Cameron <jic23@kernel.org>]

On 14/07/15 12:53, Manfred Schlaegl wrote:
> On 2015-07-13 16:16, Michael Welling wrote:
>> On Fri, Jul 10, 2015 at 10:55:30PM +0200, Manfred Schlaegl wrote:
>>> On reading in_voltage_scale of we got an NULL pointer dereference Oops.
>>>
>>> The reason for this is, that mcp320x_read_raw tries to access
>>> chip_info->resolution from struct mcp320x, but chip_info is never set.
>>>
>>> chip_info was never set since the driver was added, but there was no
>>> acute problem, because it was not referenced.
>>> The acute problem exists since
>>> b12206e917ac34bec41b9ff93d37d8bd53a2b3bc
>>> iio: adc: mcp320x. Add support for more ADCs
>>>
>>> This patch fixes the issue by setting chip_info in mcp320x_probe.
>>>
>>> Signed-off-by: Manfred Schlaegl <manfred.schlaegl@gmx.at>
>>> ---
>>>  drivers/iio/adc/mcp320x.c |    2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/drivers/iio/adc/mcp320x.c b/drivers/iio/adc/mcp320x.c
>>> index 8d9c9b9..d819823 100644
>>> --- a/drivers/iio/adc/mcp320x.c
>>> +++ b/drivers/iio/adc/mcp320x.c
>>> @@ -299,6 +299,8 @@ static int mcp320x_probe(struct spi_device *spi)
>>>  	indio_dev->channels = chip_info->channels;
>>>  	indio_dev->num_channels = chip_info->num_channels;
>>>  
>>> +	adc->chip_info = chip_info;
>>> +
>>
>> Looks good to me.
>>
>> Reviewed-by: Michael Welling <mwelling@ieee.org>
>>
>>>  	adc->transfer[0].tx_buf = &adc->tx_buf;
>>>  	adc->transfer[0].len = sizeof(adc->tx_buf);
>>>  	adc->transfer[1].rx_buf = adc->rx_buf;
>>> -- 
>>> 1.7.10.4
>>>
> 
> Thanks for reviewing!
> 
> best regards,
> manfred
> 
Applied to the fixes-togreg branch of iio.git

Michael, there are moves afoot to clarify the meaning of reviewed-by
as covering only more substantial reviews (kind of tricky on a one liner
like this!)  Hence for similar patches in future, an Acked-by may
be more appropriate.

Thanks,

Jonathan