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From:   Bill Wendling <morbo@google.com>
Date:   Thu, 9 Jun 2022 16:16:16 -0700
Message-ID: <CAGG=3QU0XJhQKJXLMayOkQSiF2yjBi2p2TEZ9KNTzU5mmye-gg@mail.gmail.com>
Subject: Re: [PATCH 00/12] Clang -Wformat warning fixes
To:     Jan Engelhardt <jengelh@inai.de>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Bill Wendling <isanbard@gmail.com>,
        Tony Luck <tony.luck@intel.com>,
        Borislav Petkov <bp@alien8.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Phillip Potter <phil@philpotter.co.uk>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
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On Thu, Jun 9, 2022 at 4:03 PM Jan Engelhardt <jengelh@inai.de> wrote:
> On Friday 2022-06-10 00:49, Bill Wendling wrote:
> >On Thu, Jun 9, 2022 at 3:25 PM Andrew Morton <akpm@linux-foundation.org> wrote:
> >> On Thu,  9 Jun 2022 22:16:19 +0000 Bill Wendling <morbo@google.com> wrote:
> >>
> >> > This patch set fixes some clang warnings when -Wformat is enabled.
> >>
> >> tldr:
> >>
> >> -       printk(msg);
> >> +       printk("%s", msg);
> >>
> >> Otherwise these changes are a
> >> useless consumer of runtime resources.
> >
> >Calling a "printf" style function is already insanely expensive.
> >[...]
> >The "printk" and similar functions all have the "__printf" attribute.
> >I don't know of a modification to that attribute which can turn off
> >this type of check.
>
> Perhaps you can split vprintk_store in the middle (after the call to
> vsnprintf), and offer the second half as a function of its own (e.g.
> "puts"). Then the tldr could be
>
> - printk(msg);
> + puts(msg);

That might be a nice compromise. Andrew, what do you think?

-bw