Re: [Outreachy kernel] [PATCH] Staging: gdm72xx: Fix sparse warning

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Oct 28, 2015 at 07:41:18PM -0700, Ksenija Stanojevic wrote:
> Calls copy_{to,from}_user() do not use '__user' annotation
> while refrencing user space pointers.
> 
> Fix following sparse warnings by passing missing __user annotation:
> 
> drivers/staging/gdm72xx/gdm_wimax.c:381:37: warning: incorrect type in
> argument 1 (different address spaces)
> drivers/staging/gdm72xx/gdm_wimax.c:381:37:    expected void [noderef]
> <asn:1>*to
> drivers/staging/gdm72xx/gdm_wimax.c:381:37:    got void *buf
> drivers/staging/gdm72xx/gdm_wimax.c:404:41: warning: incorrect type in
> argument 2 (different address spaces)
> drivers/staging/gdm72xx/gdm_wimax.c:404:41:    expected void const
> [noderef] <asn:1>*from
> drivers/staging/gdm72xx/gdm_wimax.c:404:41:    got void *buf
> 
> Signed-off-by: Ksenija Stanojevic <ksenija.stanojevic@gmail.com>
> ---
>  drivers/staging/gdm72xx/gdm_wimax.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/gdm72xx/gdm_wimax.c b/drivers/staging/gdm72xx/gdm_wimax.c
> index d9ddced..a5b4b72 100644
> --- a/drivers/staging/gdm72xx/gdm_wimax.c
> +++ b/drivers/staging/gdm72xx/gdm_wimax.c
> @@ -378,7 +378,7 @@ static int gdm_wimax_ioctl_get_data(struct data_s *dst, struct data_s *src)
>  	if (src->size) {
>  		if (!dst->buf)
>  			return -EINVAL;
> -		if (copy_to_user(dst->buf, src->buf, size))
> +		if (copy_to_user((void __user *)dst->buf, src->buf, size))

Shouldn't the variable be described as a __user pointer instead?  Don't
cast away warnings, fix the root problem.

thanks,

greg k-h