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Date: Fri, 10 Jun 2022 07:20:31 +0200
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Bill Wendling <morbo@google.com>
Cc: Jan Engelhardt <jengelh@inai.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Bill Wendling <isanbard@gmail.com>, Tony Luck <tony.luck@intel.com>,
	Borislav Petkov <bp@alien8.de>,
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Subject: Re: [PATCH 00/12] Clang -Wformat warning fixes
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In-Reply-To: <CAGG=3QU0XJhQKJXLMayOkQSiF2yjBi2p2TEZ9KNTzU5mmye-gg@mail.gmail.com>

On Thu, Jun 09, 2022 at 04:16:16PM -0700, Bill Wendling wrote:
> 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?

You would need to do that for all of the dev_printk() variants, so I
doubt that would ever be all that useful as almost no one should be
using a "raw" printk() these days.

thanks,

greg k-h