Re: [PATCH][V2] clk: uniphier: Fix potential infinite loop

[Masahiro Yamada]

On Fri, Apr 9, 2021 at 6:01 PM Colin King <colin.king@xxxxxxxxxxxxx> wrote:
>
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> The for-loop iterates with a u8 loop counter i and compares this
> with the loop upper limit of num_parents that is an int type.
> There is a potential infinite loop if num_parents is larger than
> the u8 loop counter. Fix this by making the loop counter the same
> type as num_parents.  Also make num_parents an unsigned int to
> match the return type of the call to clk_hw_get_num_parents.
>
> Addresses-Coverity: ("Infinite loop")
> Fixes: 734d82f4a678 ("clk: uniphier: add core support code for UniPhier clock driver")
>
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
>
> V2: Make num_parents an unsigned int to match return type of
>     clk_hw_get_num_parents().

Reviewed-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>




> ---
>  drivers/clk/uniphier/clk-uniphier-mux.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clk/uniphier/clk-uniphier-mux.c b/drivers/clk/uniphier/clk-uniphier-mux.c
> index 462c84321b2d..1998e9d4cfc0 100644
> --- a/drivers/clk/uniphier/clk-uniphier-mux.c
> +++ b/drivers/clk/uniphier/clk-uniphier-mux.c
> @@ -31,10 +31,10 @@ static int uniphier_clk_mux_set_parent(struct clk_hw *hw, u8 index)
>  static u8 uniphier_clk_mux_get_parent(struct clk_hw *hw)
>  {
>         struct uniphier_clk_mux *mux = to_uniphier_clk_mux(hw);
> -       int num_parents = clk_hw_get_num_parents(hw);
> +       unsigned int num_parents = clk_hw_get_num_parents(hw);
>         int ret;
>         unsigned int val;
> -       u8 i;
> +       unsigned int i;
>
>         ret = regmap_read(mux->regmap, mux->reg, &val);
>         if (ret)
> --
> 2.30.2
>


-- 
Best Regards
Masahiro Yamada