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: <9d35035d-c63e-4d11-a403-54c50e8b35c1@kylinos.cn>
Date: Mon, 14 Jul 2025 16:44:26 +0800
From: Zihuan Zhang <zhangzihuan@...inos.cn>
To: "Rafael J . Wysocki" <rafael@...nel.org>,
 Christian Brauner <brauner@...nel.org>
Cc: 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 Rafael,

Just a gentle ping on this patch.

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.

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