From: Kees Cook <keescook@chromium.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Nathan Chancellor <nathan@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
patches@lists.linux.dev, kernel test robot <lkp@intel.com>
Subject: Re: [PATCH] x86/boot: Address clang -Wimplicit-fallthrough in vsprintf()
Date: Thu, 23 May 2024 16:12:25 -0700 [thread overview]
Message-ID: <202405231603.2E810E3FC@keescook> (raw)
In-Reply-To: <20240523115734.GAZk8vLgzOzD8Tv9pq@fat_crate.local>
On Thu, May 23, 2024 at 01:57:34PM +0200, Borislav Petkov wrote:
> On Fri, May 17, 2024 at 08:18:33AM -0700, Nathan Chancellor wrote:
> > There was a patch to make Clang match GCC's behavior a few years ago but
> > I think Kees made a good argument that GCC's behavior leaves potential
> > bugs on the table, so that was not pursued further.
> >
> > https://reviews.llvm.org/D91895#2417170
>
> Really? Maybe I'm being dense but I don't see real bugs there... I see
> readability issues. :-)
There isn't a bug _here_, but this is about making the code unambiguous
everywhere in the kernel. We've already done the work to get rid of
all these warnings; this one is newly introduced, so let's get it fixed.
We don't want to have the same flow-control statement reachable from two
different "case"s where the resulting behaviors are different. Otherwise
we can't determine if a "fallthrough" is missing or intentional.
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
--
Kees Cook
next prev parent reply other threads:[~2024-05-23 23:12 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-16 14:03 [PATCH] x86/boot: Address clang -Wimplicit-fallthrough in vsprintf() Nathan Chancellor
2024-05-16 23:08 ` Justin Stitt
2024-05-17 9:51 ` Borislav Petkov
2024-05-17 15:18 ` Nathan Chancellor
2024-05-23 11:57 ` Borislav Petkov
2024-05-23 23:12 ` Kees Cook [this message]
2024-05-24 16:39 ` Borislav Petkov
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