Re: [PATCH v2] PM / devfreq: Fix kernel oops on governor module load

[Chanwoo Choi <cwchoi00@gmail.com>]

Hi,

2019년 6월 22일 (토) 오전 6:42, Ezequiel Garcia <ezequiel@collabora.com>님이 작성:
>
> A bit unexpectedly (but still documented), request_module may
> return a positive value, in case of a modprobe error.
> This is currently causing issues in the devfreq framework.
>
> When a request_module exits with a positive value, we currently
> return that via ERR_PTR. However, because the value is positive,
> it's not a ERR_VALUE proper, and is therefore treated as a
> valid struct devfreq_governor pointer, leading to a kernel oops.
>
> Fix this by returning -EINVAL if request_module returns a positive
> value.
>
> Fixes: b53b0128052ff ("PM / devfreq: Fix static checker warning in try_then_request_governor")
> Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
> ---
> Changes from v1:
> * Rework the fix as suggested by Enric and Chanwoo,
>   handling the return vaue.
> ---
>  drivers/devfreq/devfreq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 6b6991f0e873..258f70c1e48f 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -257,7 +257,7 @@ static struct devfreq_governor *try_then_request_governor(const char *name)
>                 /* Restore previous state before return */
>                 mutex_lock(&devfreq_list_lock);
>                 if (err)
> -                       return ERR_PTR(err);
> +                       return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
>
>                 governor = find_devfreq_governor(name);
>         }

Thanks you for fix-up.
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>

But, you are missing the stable mailing list. In order to apply this
fix-up patch,\
you have to send it to stable mailing list. Please send it.


-- 
Best Regards,
Chanwoo Choi