linux-kernel - Re: [PATCH 3/3] lib/vsprintf: Use pr_crit() instead of long fancy messages

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Date:   Thu, 20 May 2021 14:51:50 +0200
From:   Petr Mladek <pmladek@...e.com>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ingo Molnar <mingo@...hat.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        John Ogness <john.ogness@...utronix.de>,
        Marco Elver <elver@...gle.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Linux IOMMU <iommu@...ts.linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Embedded <linux-embedded@...r.kernel.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>
Subject: Re: [PATCH 3/3] lib/vsprintf: Use pr_crit() instead of long fancy
 messages

On Mon 2021-05-17 08:21:12, Geert Uytterhoeven wrote:
> On Wed, Mar 31, 2021 at 11:59 AM Geert Uytterhoeven
> <geert+renesas@...der.be> wrote:
> > While long fancy messages have a higher probability of being seen than
> > small messages, they may scroll of the screen fast, if visible at all,
> > and may still be missed.  In addition, they increase boot time and
> > kernel size.
> >
> > The correct mechanism to increase importance of a kernel message is not
> > to draw fancy boxes with more text, but to shout louder, i.e. increase
> > the message's reporting level.  Making sure the administrator of the
> > system is aware of such a message is a system policy, and is the
> > responsability of a user-space log daemon.
> >
> > Fix this by increasing the reporting level from KERN_WARNING to
> > KERN_CRIT, and removing irrelevant text and graphics.
> >
> > This reduces kernel size by ca. 0.5 KiB.
> >
> > Fixes: 5ead723a20e0447b ("lib/vsprintf: no_hash_pointers prints all addresses as unhashed")
> > Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
> 
> No comments?
> Unlike the cases handled by the other two patches in this series,
> this one cannot be configured out.

IMHO, the best solution would be to create a generic API for
eye-catching messages.

I am sure that WARN() is misused on many locations all over the kernel
because people just wanted eye-catching message, for example, see
https://lore.kernel.org/r/2149df3f542d25ce15d049e81d6188bb7198478c.camel@fi.rohmeurope.com

It might be a win-win solution.

Best Regards,
Petr