linux-kernel - Re: [PATCH] vsprintf: avoid misleading "(null)" for %px

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Message-ID: <CAHp75Ve5GN25xtMe3Umgd3gEQ-FEwPL2i8FmsPuLLn77+=Qm6g@mail.gmail.com>
Date:   Wed, 14 Feb 2018 16:35:35 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Petr Mladek <pmladek@...e.com>
Cc:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Adam Borowski <kilobyte@...band.pl>,
        Kees Cook <keescook@...omium.org>,
        "Tobin C. Harding" <me@...in.cc>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Joe Perches <joe@...ches.com>,
        "Roberts, William C" <william.c.roberts@...el.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        David Laight <David.Laight@...lab.com>,
        Randy Dunlap <rdunlap@...radead.org>
Subject: Re: [PATCH] vsprintf: avoid misleading "(null)" for %px

On Fri, Feb 9, 2018 at 2:03 PM, Petr Mladek <pmladek@...e.com> wrote:
> On Thu 2018-02-08 17:29:14, Andy Shevchenko wrote:
>> On Wed, Feb 7, 2018 at 5:41 PM, Petr Mladek <pmladek@...e.com> wrote:
>> > On Wed 2018-02-07 16:11:13, Geert Uytterhoeven wrote:
>>
>> > To make it clear. I was talking about "%p" format that is handled
>> > in the pointer() function in lib/vsprintf.c. The "(null)" makes
>> > sense only for the many modifiers that do deference of
>> > the pointer, e.g. "%pa", "%pE", "%ph".
>>
>> JFYI: I have a patch to eliminate those for %pE & %ph.
>>
>> Google for "lib/vsprintf: Remove useless NULL checks" as a first in
>> the series for new extension to print times.
>
> I am slightly confused. IMHO, it makes sense to printk "(null)"
> for %pE and %ph.

Yes, but isn't it done by if (!ptr) check in the very beginning of the
pointer() helper?

> Or do you just want to avoid the duplicit check in hex_string()
> and escaped_string()?

And that is as well.

> Well, it might be better to discuss this once you send the patch.

I can Cc you, though the patch is pretty independent on the series. I
can send it separately.

-- 
With Best Regards,
Andy Shevchenko