Re: [PATCH] clk: Fix pointer casting to prevent oops in devm_clk_release()

[Marek Szyprowski <m.szyprowski@samsung.com>]

On 20.06.2022 19:18, Uwe Kleine-König wrote:
> The release function is called with a pointer to the memory returned by
> devres_alloc(). I was confused about that by the code before the
> generalization that used a struct clk **ptr.
>
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Fixes: abae8e57e49a ("clk: generalize devm_clk_get() a bit")
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

> ---
> On Mon, Jun 20, 2022 at 05:26:12PM +0200, Marek Szyprowski wrote:
>>> -   clk_put(*(struct clk **)res);
>>> +   struct devm_clk_state *state = *(struct devm_clk_state **)res;
>> This should be:
>>
>> struct devm_clk_state *state = res;
>>
>> otherwise it nukes badly during cleanup:
>> [...]
> How embarrassing. I understood how I confused that, but I wonder how
> that didn't pop up earlier.
>
> FTR: I didn't test that now, but assume you did. My focus now was to get
> out an applicable patch fast.
>
> Thanks for your report
> Uwe
>
>   drivers/clk/clk-devres.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
> index c822f4ef1584..1bb086695051 100644
> --- a/drivers/clk/clk-devres.c
> +++ b/drivers/clk/clk-devres.c
> @@ -11,7 +11,7 @@ struct devm_clk_state {
>   
>   static void devm_clk_release(struct device *dev, void *res)
>   {
> -	struct devm_clk_state *state = *(struct devm_clk_state **)res;
> +	struct devm_clk_state *state = res;
>   
>   	if (state->exit)
>   		state->exit(state->clk);
>
> base-commit: abae8e57e49aa75f6db76aa866c775721523908f

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland