linux-kernel - Re: [PATCH v2 1/2] hung_task: Consolidate hung task warning into an atomic log block

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Message-ID: <2025121152-gradient-unstylish-4de3@gregkh>
Date: Thu, 11 Dec 2025 17:02:08 +0900
From: Greg KH <gregkh@...uxfoundation.org>
To: Aaron Tomlin <atomlin@...mlin.com>
Cc: akpm@...ux-foundation.org, lance.yang@...ux.dev, mhiramat@...nel.org,
	pmladek@...e.com, sean@...e.io, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] hung_task: Consolidate hung task warning into an
 atomic log block

On Wed, Dec 10, 2025 at 10:30:03PM -0500, Aaron Tomlin wrote:
> Consolidate the multi-line console output in check_hung_task() into a new
> helper function, hung_task_diagnostics().
> 
> This patch ensures the entire diagnostic block (task info, kernel
> version, and sysctl advice) is logged to the ring buffer via a single
> pr_err() call. This is critical in a concurrent environment to prevent
> message lines from interleaving with other CPU activity, thus
> maintaining contextual integrity of the warning message.

If this message is "critical", then it should not be going through the
syslog as that is NOT a "critical" way to communicate things to
userspace.

What is currently breaking today with the multi-line message that you
have?  Why is this so much more special than the normal oops / warning /
oom and other type messages that are multi-lines today?

I'm all for moving this to a single function, but I'm not ok with
multi-line messages in one pr_err() call like this, sorry.

Especially one that contains a "here is how to disable this" message
like this one does, that surely is NOT a "critical" thing.

thanks,

greg k-h