linux-kernel - Re: [PATCH] hung_task: Increment the global counter immediately

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Message-ID: <6dgy332i25cmevxyq2rbhts4nygrr4w4ijbai7vppyrqwlhmag@rdleiex3o3ig>
Date: Fri, 6 Feb 2026 15:54:15 -0500
From: Aaron Tomlin <atomlin@...mlin.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Petr Mladek <pmladek@...e.com>, Lance Yang <lance.yang@...ux.dev>, 
	neelx@...e.com, sean@...e.io, mproche@...il.com, chjohnst@...il.com, 
	nick.lange@...il.com, linux-kernel@...r.kernel.org, mhiramat@...nel.org, 
	joel.granados@...nel.org, gregkh@...uxfoundation.org
Subject: Re: [PATCH] hung_task: Increment the global counter immediately

On Wed, Feb 04, 2026 at 10:05:49AM -0800, Andrew Morton wrote:
> On Wed, 4 Feb 2026 12:04:54 +0100 Petr Mladek <pmladek@...e.com> wrote:
> 
> > A recent change allowed to reset the global counter of hung tasks using
> > the sysctl interface. A potential race with the regular check has been
> > solved by updating the global counter only once at the end of the check.
> > 
> > However, the hung task check can take a significant amount of time,
> > particularly when task information is being dumped to slow serial
> > consoles. Some users monitor this global counter to trigger immediate
> > migration of critical containers. Delaying the increment until the
> > full check completes postpones these high-priority rescue operations.
> > 
> > Update the global counter as soon as a hung task is detected. Since
> > the value is read asynchronously, a relaxed atomic operation is
> > sufficient.
> > 
> > Reported-by: Lance Yang <lance.yang@...ux.dev>
> > Closes: https://lore.kernel.org/r/f239e00f-4282-408d-b172-0f9885f4b01b@linux.dev
> > Signed-off-by: Petr Mladek <pmladek@...e.com>
> > ---
> > This is a followup patch for
> > https://lore.kernel.org/r/20260125135848.3356585-1-atomlin@atomlin.com
> > 
> > Note that I could not use commit IDs because the original
> > patchset is not in a stable tree yet. In fact, it seems
> > that it is not even in linux-next at the moment.
> 
> Yes, I've gone into "fixes and trivial stuff only" mode, as we're at -rc8.
> 
> Aaron, please incorporate Petr's fix into v8 and resend towards the end
> of the merge window?
> 
> Thanks.

Hi Andrew,

Absolutely.

Kind regards,
-- 
Aaron Tomlin

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