linux-kernel - Re: [PATCH v1] PM: sleep: Do not flag runtime PM workqueue as freezable

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: <0b8c07a6-de96-4091-96db-71fa6b95a8f7@vivo.com>
Date: Tue, 2 Dec 2025 18:36:58 +0800
From: YangYang <yang.yang@...o.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: Bart Van Assche <bvanassche@....org>, Jens Axboe <axboe@...nel.dk>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Danilo Krummrich <dakr@...nel.org>, linux-block@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
 Ulf Hansson <ulf.hansson@...aro.org>
Subject: Re: [PATCH v1] PM: sleep: Do not flag runtime PM workqueue as
 freezable

On 2025/12/2 3:58, Rafael J. Wysocki wrote:
> On Monday, December 1, 2025 7:47:46 PM CET Rafael J. Wysocki wrote:
>> On Mon, Dec 1, 2025 at 10:46 AM YangYang <yang.yang@...o.com> wrote:
> 
> [cut]
> 
>> If blk_queue_enter() or __bio_queue_enter() is allowed to race with
>> disabling runtime PM for q->dev, failure to resume q->dev is alway
>> possible and there are no changes that can be made to
>> pm_runtime_disable() to prevent that from happening.  If
>> __pm_runtime_disable() wins the race, it will increment
>> power.disable_depth and rpm_resume() will bail out when it sees that
>> no matter what.
>>
>> You should not conflate "runtime PM doesn't work when it is disabled"
>> with "asynchronous runtime PM doesn't work after freezing the PM
>> workqueue".  They are both true, but they are not the same.
> 
> So I've been testing the patch below for a few days and it will eliminate
> the latter, but even after this patch runtime PM will be disabled in
> device_suspend_late() and if the problem you are facing is still there
> after this patch, it will need to dealt with at the driver level.
> 
> Generally speaking, driver involvement is needed to make runtime PM and
> system suspend/resume work together in the majority of cases.
> 

Thank you. I'll perform some tests with this patch applied.