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

From: Maxwell Doose

Date: Mon May 25 2026 - 09:24:00 EST


Hi Dan,

On Mon, May 25, 2026 at 2:19 AM Dan Carpenter <error27@xxxxxxxxx> 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 <error27@xxxxxxxxx>
> ---
> 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))

Regardless,

Reviewed-by: Maxwell Doose <m32285159@xxxxxxxxx>

best regards,
max