Re: [PATCH 2/2] media: drxk_hard: check if parameter is not NULL

[Nick Desaulniers <ndesaulniers@google.com>]

On Fri, Dec 7, 2018 at 5:08 AM Mauro Carvalho Chehab
<mchehab+samsung@kernel.org> wrote:
>
> There is a smatch warning:
>         drivers/media/dvb-frontends/drxk_hard.c: drivers/media/dvb-frontends/drxk_hard.c:1478 scu_command() error: we previously assumed 'parameter' could be null (see line 1467)
>
> Telling that parameter might be NULL. Well, it can't, due to the
> way the driver works, but it doesn't hurt to add a check, in order
> to shut up smatch.

eh, yeah this function is kind of odd; the early return conditions are
a little tricky, but I agree that this check doesn't hurt to add.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
> ---
>  drivers/media/dvb-frontends/drxk_hard.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/dvb-frontends/drxk_hard.c b/drivers/media/dvb-frontends/drxk_hard.c
> index 84ac3f73f8fe..8ea1e45be710 100644
> --- a/drivers/media/dvb-frontends/drxk_hard.c
> +++ b/drivers/media/dvb-frontends/drxk_hard.c
> @@ -1474,9 +1474,11 @@ static int scu_command(struct drxk_state *state,
>
>         /* assume that the command register is ready
>                 since it is checked afterwards */
> -       for (ii = parameter_len - 1; ii >= 0; ii -= 1) {
> -               buffer[cnt++] = (parameter[ii] & 0xFF);
> -               buffer[cnt++] = ((parameter[ii] >> 8) & 0xFF);
> +       if (parameter) {
> +               for (ii = parameter_len - 1; ii >= 0; ii -= 1) {
> +                       buffer[cnt++] = (parameter[ii] & 0xFF);
> +                       buffer[cnt++] = ((parameter[ii] >> 8) & 0xFF);
> +               }
>         }
>         buffer[cnt++] = (cmd & 0xFF);
>         buffer[cnt++] = ((cmd >> 8) & 0xFF);
> --
> 2.19.2
>


-- 
Thanks,
~Nick Desaulniers