linux-kernel - Re: [PATCH v1] PM: sleep: core: Clear device async state upfront during suspend

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Message-ID: <CAJZ5v0iScM-1nTXuex3rhhWOhe+NcVj1X-ObKY=c5TnZk_eB7A@mail.gmail.com>
Date: Wed, 4 Feb 2026 13:11:09 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Xuewen Yan <xuewen.yan94@...il.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Linux PM <linux-pm@...r.kernel.org>, 
	LKML <linux-kernel@...r.kernel.org>, Ulf Hansson <ulf.hansson@...aro.org>, 
	Saravana Kannan <saravanak@...gle.com>, Xuewen Yan <xuewen.yan@...soc.com>
Subject: Re: [PATCH v1] PM: sleep: core: Clear device async state upfront
 during suspend

On Wed, Feb 4, 2026 at 3:57 AM Xuewen Yan <xuewen.yan94@...il.com> wrote:
>
> Hi Rafael,
>
> On Wed, Feb 4, 2026 at 4:38 AM Rafael J. Wysocki <rafael@...nel.org> wrote:
> >
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >
> > In all of the system suspend transition phases, async state of all
> > devices needs to be cleared before starting async processing for any of
> > them because the latter may race with power.work_in_progress updates for
> > the device's parent or suppliers and if it touches bit fields from the
> > same group (for example, power.must_resume or power.wakeup_path), bit
> > field corruption is possible.
> >
> > Rearrange the code accordingly.
>
> Could we use the following patch:

Yes, we can make this change.

> diff --git a/include/linux/pm.h b/include/linux/pm.h
> index 98a899858ece..afcaaa37a812 100644
> --- a/include/linux/pm.h
> +++ b/include/linux/pm.h
> @@ -681,10 +681,10 @@ struct dev_pm_info {
>         struct list_head        entry;
>         struct completion       completion;
>         struct wakeup_source    *wakeup;
> +       bool                    work_in_progress;       /* Owned by
> the PM core */
>         bool                    wakeup_path:1;
>         bool                    syscore:1;
>         bool                    no_pm_callbacks:1;      /* Owned by
> the PM core */
> -       bool                    work_in_progress:1;     /* Owned by
> the PM core */
>         bool                    smart_suspend:1;        /* Owned by
> the PM core */
>         bool                    must_resume:1;          /* Owned by
> the PM core */
>         bool                    may_skip_resume:1;      /* Set by subsystems */
>
> Due to byte alignment, the size of struct dev_pm_info remains unchanged,

I had considered making it, but I thought it would cause struct
dev_pm_info to grow.

> while also preventing concurrency issues between work_in_progress and
> other variables. Additionally, with this modification, there’s no need to traverse the
> device list twice.

Sure.

I'll just commit the above change with your sign-off, please let me
know if there are any issues with that.

Thanks!