Thx Greg,
Pls ignore this thread. Already correct to the normal linux-kernel@xxxxxxxxxxxxxxx in another email thread.
Thx and BRs,
Aiqun Yu (Maria)
-----Original Message-----
From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Sent: Thursday, October 27, 2022 3:24 PM
To: Aiqun Yu (QUIC) <quic_aiquny@xxxxxxxxxxx>
Cc: linus.walleij@xxxxxxxxxx; linux-gpio@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx
Subject: Re: [PATCH] pinctrl: core: Make p->state in order in pinctrl_commit_state
WARNING: This email originated from outside of Qualcomm. Please be wary of any links or attachments, and do not enable macros.
On Thu, Oct 27, 2022 at 02:51:10PM +0800, Maria Yu wrote:
> We've got a dump that current cpu is in pinctrl_commit_state, the
> old_state != p->state while the stack is still in the process of
> pinmux_disable_setting. So it means even if the current p->state is
> changed in new state, the settings are not yet up-to-date enabled
> complete yet.
>
> Currently p->state in different value to synchronize the
> pinctrl_commit_state behaviors. The p->state will have transaction
> like old_state -> NULL -> new_state. When in old_state, it will try to
> disable all the all state settings. And when after new state settings
> enabled, p->state will changed to the new state after that. So use
> smp_mb to synchronize the p->state variable and the settings in order.
> ---
> drivers/pinctrl/core.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c index
> 9e57f4c62e60..cd917a5b1a0a 100644
> --- a/drivers/pinctrl/core.c
> +++ b/drivers/pinctrl/core.c
> @@ -1256,6 +1256,7 @@ static int pinctrl_commit_state(struct pinctrl *p, struct pinctrl_state *state)
> }
> }
>
> + smp_mb();
> p->state = NULL;
>
> /* Apply all the settings for the new state - pinmux first */ @@
> -1305,6 +1306,7 @@ static int pinctrl_commit_state(struct pinctrl *p, struct pinctrl_state *state)
> pinctrl_link_add(setting->pctldev, p->dev);
> }
>
> + smp_mb();
> p->state = state;
>
> return 0;
> --
> 2.17.1
>
<formletter>
This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.
</formletter>
