On Wed, Oct 30, 2024 at 01:47:20PM +0300, Dan Carpenter wrote:
> On Wed, Oct 30, 2024 at 10:58:01AM +0100, Vasileios Amoiridis wrote:
> > On Wed, Oct 30, 2024 at 12:26:13PM +0300, Dan Carpenter wrote:
> > > Hello Vasileios Amoiridis,
> > >
> > > Commit 9b4071ab8cbe ("iio: chemical: bme680: generalize read_*()
> > > functions") from Oct 21, 2024 (linux-next), leads to the following
> > > Smatch static checker warning:
> > >
> > > drivers/iio/chemical/bme680_core.c:760 bme680_read_raw()
> > > warn: passing casted pointer '&chan_val' to 'bme680_read_temp()' 32 vs 16.
> > >
> > > drivers/iio/chemical/bme680_core.c
> > > 738 static int bme680_read_raw(struct iio_dev *indio_dev,
> > > 739 struct iio_chan_spec const *chan,
> > > 740 int *val, int *val2, long mask)
> > > 741 {
> > > 742 struct bme680_data *data = iio_priv(indio_dev);
> > > 743 int chan_val, ret;
> > > 744
> > > 745 guard(mutex)(&data->lock);
> > > 746
> > > 747 /* set forced mode to trigger measurement */
> > > 748 ret = bme680_set_mode(data, true);
> > > 749 if (ret < 0)
> > > 750 return ret;
> > > 751
> > > 752 ret = bme680_wait_for_eoc(data);
> > > 753 if (ret)
> > > 754 return ret;
> > > 755
> > > 756 switch (mask) {
> > > 757 case IIO_CHAN_INFO_PROCESSED:
> > > 758 switch (chan->type) {
> > > 759 case IIO_TEMP:
> > > --> 760 ret = bme680_read_temp(data, (s16 *)&chan_val);
> > >
> > > The bme680_read_temp() function takes an s16 pointer but we're passing a s32.
> > > This will not work on big endian systems and even on little endian systems, we
> > > haven't initialized the last 16 bits of chan_val so it's an uninitialized
> > > variable bug.
> > >
> >
> > Hi Dan,
> >
> > Thanks for letting me know! What I could do is instead of reusing the
> > int chan_val, I could use a local s16 temp_chan_val so there is no need
> > for typecasting here.
>
> That works. Not a fan of the name though. "temp" means "temperature" and "tmp"
> means "temporary". chan_val16 perhaps?
>
> regards,
> dan carpenter
>
That's the reason I used temp in the name, because we are reading a
temperature channel in this line.
Cheers,
Vasilis
