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 <ZYvjiqX6EsL15moe@perf> <2023122701-mortify-deed-4e66@gregkh>
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From: "Rafael J. Wysocki" <rafael@kernel.org>
Date: Wed, 27 Dec 2023 18:44:51 +0100
Message-ID: <CAJZ5v0hGd0LzaBkiPYV3D7fnTm9aVOn6eT84q-_r1Rr-1Vupow@mail.gmail.com>
Subject: Re: [BUG] mutex deadlock of dpm_resume() in low memory situation
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Youngmin Nam <youngmin.nam@samsung.com>, rafael@kernel.org, len.brown@intel.com, 
	pavel@ucw.cz, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, 
	d7271.choe@samsung.com, janghyuck.kim@samsung.com, hyesoo.yu@samsung.com
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On Wed, Dec 27, 2023 at 5:08=E2=80=AFPM Greg KH <gregkh@linuxfoundation.org=
> wrote:
>
> On Wed, Dec 27, 2023 at 05:42:50PM +0900, Youngmin Nam wrote:
> > Could you look into this issue ?
>
> Can you submit a patch that resolves the issue for you, as you have a
> way to actually test this out?  That would be the quickest way to get it
> resolved, and to help confirm that this is even an issue at all.

This is a real problem, unfortunately, and the fix would require some
infra changes AFAICS.

To address it, we would need a variant of async_schedule_node_domain()
that would bail out on low memory instead of attempting to run the
stuff synchronously which is harmful (not just for the deadlock
reason) in the suspend-resume paths.

I'll try to cut a test patch shortly.