linux-kernel - Re: [PATCH v7 1/3] scanf: remove redundant debug logs

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Message-ID: <Z6uFlh6TgXTnwHI-@smile.fi.intel.com>
Date: Tue, 11 Feb 2025 19:15:02 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Tamir Duberstein <tamird@...il.com>
Cc: David Gow <davidgow@...gle.com>, Petr Mladek <pmladek@...e.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Sergey Senozhatsky <senozhatsky@...omium.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Shuah Khan <shuah@...nel.org>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v7 1/3] scanf: remove redundant debug logs

On Tue, Feb 11, 2025 at 11:02:59AM -0500, Tamir Duberstein wrote:
> On Tue, Feb 11, 2025 at 10:58 AM Andy Shevchenko
> <andriy.shevchenko@...ux.intel.com> wrote:
> > On Tue, Feb 11, 2025 at 10:50:33AM -0500, Tamir Duberstein wrote:
> > > On Tue, Feb 11, 2025 at 10:42 AM Andy Shevchenko
> > > <andriy.shevchenko@...ux.intel.com> wrote:
> > > > On Tue, Feb 11, 2025 at 10:13:37AM -0500, Tamir Duberstein wrote:
> > > > > The test already prints the same information on failure; remove
> > > > > redundant pr_debug() logs.

...

> > > > > -     pr_debug("\"%s\", \"%s\" ->\n", str, fmt);                              \
> > > >
> > > > What *if* the n_args == 0 here?
> > >
> > > Then there's no assertion in this block, so the test cannot possibly fail here.
> >
> > Correct, but I'm talking about this in a scope of the removed debug print.
> > I.o.w. how would we even know that this was the case?
> >
> > (I'm not objecting removal, what I want from you is to have a descriptive and
> >  explanatory commit message that's answers to "why is this needed?" and "why is
> >  it safe to do?")
> 
> The true answer to "why is this needed" is Petr requested it in
> https://lore.kernel.org/all/Z6s2eqh0jkYHntUL@pathway.suse.cz/ (again,
> lore is having issues):
> 
> On Tue, Feb 11, 2025 at 6:37 AM Petr Mladek <pmladek@...e.com> wrote:

[...]

> > But when thinking more about it. I think that even pr_debug() is not
> > the right solution.
> >
> > IMHO, we really want to print these details only when the test fails.
> >
> > Best Regards,
> > Petr
> 
> The commit message already answers "why is it safe to do":

Not really. It answers that "why is it safe to do when test case fails?".

> > The test already prints the same information on failure; remove
> > redundant pr_debug() logs.
> 
> Perhaps what you're asking for is an assertion to be added if n_args
> == 0? I think that would make sense. Does it belong in this series?

I don't know if it's possible case. I don't know if we need an assertion.
Please, research.

-- 
With Best Regards,
Andy Shevchenko