linux-kernel - Re: Workqueue regression

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]

Date: Thu, 1 Feb 2024 15:52:19 -1000
From: Tejun Heo <tj@...nel.org>
To: Konrad Dybcio <konradybcio@...nel.org>
Cc: linux-kernel@...r.kernel.org, Naohiro.Aota@....com,
	kernel-team@...a.com, Bjorn Andersson <andersson@...nel.org>
Subject: Re: Workqueue regression

Hello,

On Thu, Feb 01, 2024 at 09:57:59PM +0100, Konrad Dybcio wrote:
> So, commit "Implement system-wide nr_active enforcement for unbound workqueues"
> broke *something* and now performing a suspend-wakeup cycle on a Qualcomm
> SC8280XP-based (arm64) platform hangs when performing the resume tasks,
> presumably somewhere near PCIe reinitialization (but that may be a red herring).
> 
> Reverting the commit (and the ones on top of it due to conflicts) fixes
> the issue on next-20240130 and later (plus some out-of-tree patches that
> are largely unrelated).
> 
> Not sure where to start looking.

Hmm... sorry about that. Can you please boot with `console_no_suspend` and
retry? Once the system gets stuck, you can wait for several minutes till the
workqueue watchdog triggers and dumps the state or, if you can, trigger
`sysrq-t` which has workqueue state dump at the end.

If the system doesn't become live enough after suspend/resume cycle to get
more info, the following might help:

$ echo test_resume > /sys/power/disk
$ echo disk > /sys/power/state

That should walk most of the hibernation/wakeup path which is pretty simliar
to suspend/resume path without touching system power state.

Thanks.

-- 
tejun