linux-kernel - Re: [PATCH] printk: save loglevel before console

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Message-ID: <87eddcsqzd.fsf@jogness.linutronix.de>
Date: Fri, 16 Feb 2024 10:28:46 +0106
From: John Ogness <john.ogness@...utronix.de>
To: Stephen Brennan <stephen.s.brennan@...cle.com>,
 linux-kernel@...r.kernel.org
Cc: Petr Mladek <pmladek@...e.com>, Steven Rostedt <rostedt@...dmis.org>,
 Sergey Senozhatsky <senozhatsky@...omium.org>, Stephen Brennan
 <stephen.s.brennan@...cle.com>
Subject: Re: [PATCH] printk: save loglevel before console_verbose()

On 2024-02-15, Stephen Brennan <stephen.s.brennan@...cle.com> wrote:
> In panic() cases, console_verbose() is called, clobbering the
> console_loglevel value. If the bug which led to the panic related to
> printk, it can be useful to know the log level prior to the
> console_verbose() call.

I've done a *lot* of printk debugging over the past 6 years and have
never had a case where this would be useful (or even interesting).

I assume there is some rare and particular scenario you are trying to
debug. And once you've debugged it, it is no longer useful for you
either.

IMHO this does not warrant adding an extra global variable for all Linux
users.

When Petr gets back from vacation, maybe he will have a different
opinion.

John Ogness