linux-kernel - Re: [PATCH v5] printk: Userspace format enumeration support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <YFHAdUB4lu4mJ9Ar@alley>
Date:   Wed, 17 Mar 2021 09:40:21 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     Chris Down <chris@...isdown.name>
Cc:     Rasmus Villemoes <linux@...musvillemoes.dk>,
        linux-kernel@...r.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        John Ogness <john.ogness@...utronix.de>,
        Johannes Weiner <hannes@...xchg.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kees Cook <keescook@...omium.org>, kernel-team@...com
Subject: Re: [PATCH v5] printk: Userspace format enumeration support

On Tue 2021-03-16 14:28:12, Chris Down wrote:
> Rasmus Villemoes writes:
> > I think it's pointless renaming the symbol to _printk, with all the
> > churn and reduced readability that involves (especially when reading
> > assembly "why are we calling _printk and not printk here?"). There's
> > nothing wrong with providing a macro wrapper by the same name
> > 
> > #define printk(bla bla) ({ do_stuff; printk(bla bla); })
> > 
> > Only two places would need to be updated to surround the word printk in
> > parentheses to suppress macro expansion: The declaration and the
> > definition of printk. I.e.
> > 
> > int (printk)(const char *s, ...)
> 
> Hmm, I'm indifferent to either. Personally I don't like the ambiguity of
> having both a macro and function share the same name and having to think
> "what's the preprocessor context here?".

I would prefer to keep _printk. I agree that it creates some churn but
it is easier to see what is going on. Also cscope is able to
find the right thing.

Otherwise, Rasmus, thanks a lot for the review and great hints
about the macro storing the metadata into the elf section.
I am not familiar with these things.

Best Regards,
Petr