Re: [PATCH] clk: clk-loongson2: Fix the number count of clk provider

[Stephen Boyd <sboyd@kernel.org>]

Quoting Binbin Zhou (2024-12-24 22:05:59)
> Since commit 02fb4f008433 ("clk: clk-loongson2: Fix potential buffer
> overflow in flexible-array member access"), the clk provider register is
> failed.
> 
> The count of `clks_num` is shown below:
> 
>         for (p = data; p->name; p++)
>                 clks_num++;
> 
> In fact, `clks_num` represents the number of SoC clocks and should be
> expressed as the maximum value of the clock binding id in use (p->id + 1).
> 
> Now we fix it to avoid the following error when trying to register a clk
> provider:
> 
> [ 13.409595] of_clk_hw_onecell_get: invalid index 17
> 
> Fixes: 02fb4f008433 ("clk: clk-loongson2: Fix potential buffer overflow in flexible-array member access")
> Cc: stable@vger.kernel.org
> Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
> ---

It's common practice to Cc the author of a patch in Fixes. Please do it
next time.

>  drivers/clk/clk-loongson2.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clk-loongson2.c b/drivers/clk/clk-loongson2.c
> index 6bf51d5a49a1..b1b2038acd0b 100644
> --- a/drivers/clk/clk-loongson2.c
> +++ b/drivers/clk/clk-loongson2.c
> @@ -294,7 +294,7 @@ static int loongson2_clk_probe(struct platform_device *pdev)
>                 return -EINVAL;
>  
>         for (p = data; p->name; p++)
> -               clks_num++;
> +               clks_num = max(clks_num, p->id + 1);

NULL is a valid clk. Either fill the onecell data with -ENOENT error
pointers, or stop using it and implement a custom version of
of_clk_hw_onecell_get() that doesn't allow invalid clks to be requested
from this provider.

>  
>         clp = devm_kzalloc(dev, struct_size(clp, clk_data.hws, clks_num),
>                            GFP_KERNEL);