Re: [PATCH -next] hwrng: Fix unsigned comparison with less than zero

[Sumit Garg]

On Tue, 19 Feb 2019 at 12:04, YueHaibing <yuehaibing@xxxxxxxxxx> wrote:
>
> The return from the call to tee_client_invoke_func can be a
> negative error code however this is being assigned to an
> unsigned variable 'ret' hence the check is always false.
> Fix this by making 'ret' an int.
>
> Detected by Coccinelle ("Unsigned expression compared with zero:
> ret < 0")
>
> Fixes: 5fe8b1cc6a03 ("hwrng: add OP-TEE based rng driver")
> Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>

Reviewed-by: Sumit Garg <sumit.garg@xxxxxxxxxx>

> ---
>  drivers/char/hw_random/optee-rng.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/hw_random/optee-rng.c b/drivers/char/hw_random/optee-rng.c
> index 2b9fc8a..e9f4e10 100644
> --- a/drivers/char/hw_random/optee-rng.c
> +++ b/drivers/char/hw_random/optee-rng.c
> @@ -73,7 +73,7 @@ struct optee_rng_private {
>  static size_t get_optee_rng_data(struct optee_rng_private *pvt_data,
>                                  void *buf, size_t req_size)
>  {
> -       u32 ret = 0;
> +       int ret = 0;
>         u8 *rng_data = NULL;
>         size_t rng_size = 0;
>         struct tee_ioctl_invoke_arg inv_arg = {0};
> @@ -172,7 +172,7 @@ static struct optee_rng_private pvt_data = {
>
>  static int get_optee_rng_info(struct device *dev)
>  {
> -       u32 ret = 0;
> +       int ret = 0;
>         struct tee_ioctl_invoke_arg inv_arg = {0};
>         struct tee_param param[4] = {0};
>
> --
> 2.7.0
>
>