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Sender: Tejun Heo <htejun@gmail.com>
Date: Thu, 1 Feb 2024 15:52:19 -1000
From: Tejun Heo <tj@kernel.org>
To: Konrad Dybcio <konradybcio@kernel.org>
Cc: linux-kernel@vger.kernel.org, Naohiro.Aota@wdc.com,
	kernel-team@meta.com, Bjorn Andersson <andersson@kernel.org>
Subject: Re: Workqueue regression
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References: <b3d08cd8-d77f-45dd-a2c3-4a4db5a98dfa@kernel.org>
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In-Reply-To: <b3d08cd8-d77f-45dd-a2c3-4a4db5a98dfa@kernel.org>

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