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

[Michael Welling <mwelling@ieee.org>]

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
>