[V2] clk: uniphier: Fix potential infinite loop

Commit Message

Colin King April 9, 2021, 9:01 a.m. UTC

From: Colin Ian King <[e-mail]>

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 <[e-mail]>
---

V2: Make num_parents an unsigned int to match return type of
    clk_hw_get_num_parents().

---
 drivers/clk/uniphier/clk-uniphier-mux.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Masahiro Yamada April 9, 2021, 6:28 p.m. UTC | #1

On Fri, Apr 9, 2021 at 6:01 PM Colin King <[e-mail]> wrote:
>
> From: Colin Ian King <[e-mail]>
>
> 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 <[e-mail]>
> ---
>
> V2: Make num_parents an unsigned int to match return type of
>     clk_hw_get_num_parents().

Reviewed-by: Masahiro Yamada <[e-mail]>




> ---
>  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
>

Stephen Boyd April 13, 2021, 2:10 a.m. UTC | #2

Quoting Colin King (2021-04-09 02:01:04)
> From: Colin Ian King <[e-mail]>
> 
> 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 <[e-mail]>
> ---

Applied to clk-next

Patch

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)