linux-kernel - Re: [PATCH v1] PM: suspend: clean up redundant filesystems

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAJZ5v0g22fMDc21yV2svePf_4BWZRrcy+b3-efpbfAGLpa2=Lw@mail.gmail.com>
Date: Mon, 14 Jul 2025 19:57:55 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Zihuan Zhang <zhangzihuan@...inos.cn>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>, Christian Brauner <brauner@...nel.org>, 
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@...nel.org>, linux-pm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] PM: suspend: clean up redundant filesystems_freeze/thaw
 handling

Hi,

On Mon, Jul 14, 2025 at 10:44 AM Zihuan Zhang <zhangzihuan@...inos.cn> wrote:
>
> Hi Rafael,
>
> Just a gentle ping on this patch.

I've lost track of it for some reason, sorry.

> I realized I forgot to mention an important motivation in the changelog:
> calling filesystems_freeze() twice (from both suspend_prepare() and
> enter_state()) lead to a black screen and make the system unable to resume..
>
> This patch avoids the duplicate call and resolves that issue.

Now applied as a fix for 6.16-rc7, thank you!

> 在 2025/7/12 11:08, Zihuan Zhang 写道:
> > The recently introduced support for freezing filesystems during system
> > suspend included calls to filesystems_freeze() in both suspend_prepare()
> > and enter_state(), as well as calls to filesystems_thaw() in both
> > suspend_finish() and the Unlock path in enter_state(). These are
> > redundant.
> >
> > - filesystems_freeze() is already called in suspend_prepare(), which is
> >    the proper and consistent place to handle pre-suspend operations. The
> > second call in enter_state() is unnecessary and removed.
> >
> > - filesystems_thaw() is invoked in suspend_finish(), which covers
> >    successful suspend/resume paths. In the failure case , we add a call
> > to filesystems_thaw() only when needed, avoiding the duplicate call in
> > the general Unlock path.
> >
> > This change simplifies the suspend code and avoids repeated freeze/thaw
> > calls, while preserving correct ordering and behavior.
> >
> > Fixes: eacfbf74196f91e4c26d9f8c78e1576c1225cd8c ("power: freeze filesystems during suspend/resume")
> > Signed-off-by: Zihuan Zhang <zhangzihuan@...inos.cn>
> > ---
> >   kernel/power/suspend.c | 4 +---
> >   1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> > index bb608b68fb30..8f3e4c48d5cd 100644
> > --- a/kernel/power/suspend.c
> > +++ b/kernel/power/suspend.c
> > @@ -384,6 +384,7 @@ static int suspend_prepare(suspend_state_t state)
> >               return 0;
> >
> >       dpm_save_failed_step(SUSPEND_FREEZE);
> > +     filesystems_thaw();
> >       pm_notifier_call_chain(PM_POST_SUSPEND);
> >    Restore:
> >       pm_restore_console();
> > @@ -593,8 +594,6 @@ static int enter_state(suspend_state_t state)
> >               ksys_sync_helper();
> >               trace_suspend_resume(TPS("sync_filesystems"), 0, false);
> >       }
> > -     if (filesystem_freeze_enabled)
> > -             filesystems_freeze();
> >
> >       pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
> >       pm_suspend_clear_flags();
> > @@ -614,7 +613,6 @@ static int enter_state(suspend_state_t state)
> >       pm_pr_dbg("Finishing wakeup.\n");
> >       suspend_finish();
> >    Unlock:
> > -     filesystems_thaw();
> >       mutex_unlock(&system_transition_mutex);
> >       return error;
> >   }
> Thanks,
> Zihuan Zhang