Re: [PATCH] iio: dac: ad3552r-hs: fix uninitialized data ni ad3552r_hs_write_data_source()

[Jonathan Cameron]

On Mon, 25 May 2026 08:21:51 -0500
Maxwell Doose <m32285159@xxxxxxxxx> wrote:

> Hi Dan,
> 
> On Mon, May 25, 2026 at 2:16 AM Dan Carpenter <error27@xxxxxxxxx> wrote:
> >
> > If the *ppos value is non-zero then the simple_write_to_buffer() function
> > won't initialized the start of the buf[] buffer.  Non-zero values for
> > *ppos won't work here generally, so just test for them and return -EINVAL
> > at the start of the function.
> >  
> 
> Please see my other email, you're also returning -ENOSPC instead of
> -EINVAL here...
> 
Good spot. Tweaked whilst applying.

Applied to the fixes-togreg branch of iio.git and marked for stable.

Thanks

Jonathan
> >
> > Fixes: b1c5d68ea66e ("iio: dac: ad3552r-hs: add support for internal ramp")
> > Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>
> > ---
> >  drivers/iio/dac/ad3552r-hs.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/iio/dac/ad3552r-hs.c b/drivers/iio/dac/ad3552r-hs.c
> > index a9578afa7015..6bc64f53bce9 100644
> > --- a/drivers/iio/dac/ad3552r-hs.c
> > +++ b/drivers/iio/dac/ad3552r-hs.c
> > @@ -549,7 +549,7 @@ static ssize_t ad3552r_hs_write_data_source(struct file *f,
> >
> >         guard(mutex)(&st->lock);
> >
> > -       if (count >= sizeof(buf))
> > +       if (*ppos != 0 || count >= sizeof(buf))
> >                 return -ENOSPC;
> >  
> 
> See above comment.
> 
> best regards,
> max
> 
> 
> 
> >         ret = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, userbuf,
> > --
> > 2.53.0
> >
> >