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From: John Stultz <jstultz@google.com>
Date: Sat, 4 May 2024 01:39:23 -0700
Message-ID: <CANDhNCoefufFFR=nbqo3Gn-NAXBqnLMXuZujz-cTzD_weO84+A@mail.gmail.com>
Subject: Re: WW_MUTEX_SELFTEST hangs w/ 6.9-rc workqueue changes
To: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>, Will Deacon <will@kernel.org>, 
	Ingo Molnar <mingo@redhat.com>, Peter Zijlstra <peterz@infradead.org>, 
	LKML <linux-kernel@vger.kernel.org>, kernel-team@android.com
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On Fri, May 3, 2024 at 7:47=E2=80=AFPM Tejun Heo <tj@kernel.org> wrote:
> On Fri, May 03, 2024 at 06:01:49PM -0700, John Stultz wrote:
> > Hey All,
> >    In doing some local testing, I noticed I've started to see boot
> > stalls with CONFIG_WW_MUTEX_SELFTEST with 6.9-rc on a 64cpu qemu
> > environment.
> >
> > I've bisected the problem down to:
> >   5797b1c18919 (workqueue: Implement system-wide nr_active enforcement
> > for unbound workqueues)
> > + the fix needed for that change:
> >   15930da42f89 (workqueue: Don't call cpumask_test_cpu() with -1 CPU
> > in wq_update_node_max_active())
>
> This should be fixed by d40f92020c7a ("workqueue: The default node_nr_act=
ive
> should have its max set to max_active"). Can you please confirm the fix?

Ah! Thank you, that does resolve the issue!

> Thanks and sorry about the hassle.

Thanks so much for the quick response (can't beat a fix already in the tree=
!)
-john