linux-kernel - Re: [PATCH 1/2] thermal: netlink: Improve the initcall ordering

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Message-ID: <CAHLCerNfKGmEz9g98VA6iMYy7MjfwfH=gaF9KR0o_qpJwFPekA@mail.gmail.com>
Date:   Mon, 20 Jul 2020 11:13:21 +0530
From:   Amit Kucheria <amit.kucheria@...aro.org>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Zhang Rui <rui.zhang@...el.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux PM list <linux-pm@...r.kernel.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH 1/2] thermal: netlink: Improve the initcall ordering

On Fri, Jul 17, 2020 at 10:12 PM Daniel Lezcano
<daniel.lezcano@...aro.org> wrote:
>
> The initcalls like to play joke. In our case, the thermal-netlink
> initcall is called after the thermal-core initcall but this one sends
> a notification before the former is initialzed. No issue was spotted,

typo: initialized

> but it could lead to a memory corruption, so instead of relying on the
> core_initcall for the thermal-netlink, let's initialize directly from
> the thermal-core init routine, so we have full control of the init
> ordering.

> Reported-by: Marek Szyprowski <m.szyprowski@...sung.com>
> Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>

Reviewed-by: Amit Kucheria <amit.kucheria@...aro.org>

> ---
>  drivers/thermal/thermal_core.c    | 4 ++++
>  drivers/thermal/thermal_netlink.c | 3 +--
>  drivers/thermal/thermal_netlink.h | 6 ++++++
>  3 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 25ef29123f72..c2e7d7aaa354 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -1581,6 +1581,10 @@ static int __init thermal_init(void)
>  {
>         int result;
>
> +       result = thermal_netlink_init();
> +       if (result)
> +               goto error;
> +
>         mutex_init(&poweroff_lock);
>         result = thermal_register_governors();
>         if (result)
> diff --git a/drivers/thermal/thermal_netlink.c b/drivers/thermal/thermal_netlink.c
> index dd0a3b889674..42eace7401da 100644
> --- a/drivers/thermal/thermal_netlink.c
> +++ b/drivers/thermal/thermal_netlink.c
> @@ -641,8 +641,7 @@ static struct genl_family thermal_gnl_family __ro_after_init = {
>         .n_mcgrps       = ARRAY_SIZE(thermal_genl_mcgrps),
>  };
>
> -static int __init thermal_netlink_init(void)
> +int __init thermal_netlink_init(void)
>  {
>         return genl_register_family(&thermal_gnl_family);
>  }
> -core_initcall(thermal_netlink_init);
> diff --git a/drivers/thermal/thermal_netlink.h b/drivers/thermal/thermal_netlink.h
> index 0ec28d105da5..828d1dddfa98 100644
> --- a/drivers/thermal/thermal_netlink.h
> +++ b/drivers/thermal/thermal_netlink.h
> @@ -6,6 +6,7 @@
>
>  /* Netlink notification function */
>  #ifdef CONFIG_THERMAL_NETLINK
> +int __init thermal_netlink_init(void);
>  int thermal_notify_tz_create(int tz_id, const char *name);
>  int thermal_notify_tz_delete(int tz_id);
>  int thermal_notify_tz_enable(int tz_id);
> @@ -23,6 +24,11 @@ int thermal_notify_cdev_delete(int cdev_id);
>  int thermal_notify_tz_gov_change(int tz_id, const char *name);
>  int thermal_genl_sampling_temp(int id, int temp);
>  #else
> +static inline int thermal_netlink_init(void)
> +{
> +       return 0;
> +}
> +
>  static inline int thermal_notify_tz_create(int tz_id, const char *name)
>  {
>         return 0;
> --
> 2.17.1
>