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Date: Thu, 15 Feb 2024 10:55:09 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>,
 linux-kernel@vger.kernel.org, fuyuanli <fuyuanli@didiglobal.com>
Subject: Re: [PATCH] kernel/hung_task.c: export
 sysctl_hung_task_timeout_secs
Message-Id: <20240215105509.b7b3c87c24ed35cdfb111f34@linux-foundation.org>
In-Reply-To: <Zc2giqMeZhxuDSU9@infradead.org>
References: <20240209070935.1529844-1-kent.overstreet@linux.dev>
	<Zc2giqMeZhxuDSU9@infradead.org>
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On Wed, 14 Feb 2024 21:26:34 -0800 Christoph Hellwig <hch@infradead.org> wrote:

> On Fri, Feb 09, 2024 at 02:09:35AM -0500, Kent Overstreet wrote:
> > needed for thread_with_file; also rare but not unheard of to need this
> > in module code, when blocking on user input.
> > 
> > one workaround used by some code is wait_event_interruptible() - but
> > that can be buggy if the outer context isn't expecting unwinding.
> 
> I don't think just exporting the variable ad thus allowing write
> access is a good idea.  If we want to keep going down the route of
> this hack we should add an accessor function that returns the value.
> 
> The cleaner solution would be a new task state that explicitly
> marks code than can sleep forever without triggerring the hang
> check.  Although this might be a bit invaѕive and take a while.

A new PF_whatever flag would solve that simply?

Which are the potential use sites for such a thing?