Re: [PATCH] iio: core: fix uninitialized data in debugfs

On Mon, May 25, 2026 at 08:17:28AM -0500, Maxwell Doose wrote:
> Hi Dan,
> 
> On Mon, May 25, 2026 at 2:19 AM Dan Carpenter <[email protected]> wrote:
> >
> > If *ppos is non-zero then simple_write_to_buffer() will not initialize
> > the start of buf[].  Non zero values for *ppos aren't going to work
> > anyway.  Test for them at the start of the function and return -EINVAL.
> >
> > Fixes: 6d5dd486c715 ("iio: core: make use of simple_write_to_buffer()")
> > Signed-off-by: Dan Carpenter <[email protected]>
> > ---
> > The original copy_from_user() code was better:
> > https://staticthinking.wordpress.com/2026/05/23/simple_write_to_buffer-is-complicated/
> > ---
> >  drivers/iio/industrialio-core.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> 
> Codewise looks good but often times people will prefer
> 
> if (*ppos || count >= sizeof(buf))
> 
> over
> 
> if (*ppos != 0 || count >= sizeof(buf))

In this context, I feel like either is acceptable since zero
represents the number zero.  I have a blog about that which I have
been trying to promote.  #SEO

https://staticthinking.wordpress.com/2024/02/20/when-to-use-0/

> 
> Regardless,
> 
> Reviewed-by: Maxwell Doose <[email protected]>
> 

Thanks.  And you're other comments with regards to -EINVAL and
-ENOSPC are obviously correct.

regards,
dan carpenter