Re: [PATCH] iio: hmc: fix a potential NULL pointer dereference

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 12 Mar 2019 02:19:25 -0500
Kangjie Lu <kjlu@umn.edu> wrote:

> > On Mar 9, 2019, at 12:29 PM, Jonathan Cameron <jic23@kernel.org> wrote:
> > 
> > On Sat, 9 Mar 2019 14:42:09 +0100
> > Tomasz Duszynski <tduszyns@gmail.com <mailto:tduszyns@gmail.com>> wrote:
> >   
> >> On Fri, Mar 08, 2019 at 11:15:32PM -0600, Kangjie Lu wrote:  
> >>> devm_regmap_init_i2c may fail and return NULL. The fix returns
> >>> the error when it fails.
> >>> 
> >>> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> >>> ---
> >>> drivers/iio/magnetometer/hmc5843_i2c.c | 7 ++++++-
> >>> 1 file changed, 6 insertions(+), 1 deletion(-)
> >>> 
> >>> diff --git a/drivers/iio/magnetometer/hmc5843_i2c.c b/drivers/iio/magnetometer/hmc5843_i2c.c
> >>> index 3de7f4426ac4..c0cd0823f8d5 100644
> >>> --- a/drivers/iio/magnetometer/hmc5843_i2c.c
> >>> +++ b/drivers/iio/magnetometer/hmc5843_i2c.c
> >>> @@ -58,8 +58,13 @@ static const struct regmap_config hmc5843_i2c_regmap_config = {
> >>> static int hmc5843_i2c_probe(struct i2c_client *cli,
> >>> 			     const struct i2c_device_id *id)
> >>> {
> >>> +	struct regmap *devm_regmap = devm_regmap_init_i2c(cli,
> >>> +			&hmc5843_i2c_regmap_config);
> >>> +	if (IS_ERR(devm_regmap))
> >>> +		return PTR_ERR(devm_regmap);    
> >> 
> >> This fixes only one part of the problem leaving identical spi issue
> >> behind. I guess this check should be part of *common_probe().  
> > It could be, but that somewhat hides the error checking.
> > 
> > I'd prefer to see it fixed like this, but in both here and the spi
> > file.  Both this and spi in one patch would be great!  
> 
> I’ve submitted the patch for spi as well.
> 
Ah. I missed it because of inconsistent patch naming.
Anyhow, there were some minor suggestions for that patch so please
send a v2 with the two combined.

Thanks

Jonathan

> > 
> > Thanks,
> > 
> > Jonathan
> >   
> >>   
> >>> +
> >>> 	return hmc5843_common_probe(&cli->dev,
> >>> -			devm_regmap_init_i2c(cli, &hmc5843_i2c_regmap_config),
> >>> +			devm_regmap,
> >>> 			id->driver_data, id->name);
> >>> }
> >>> 
> >>> --
> >>> 2.17.1  
>