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Date: Wed, 9 Apr 2025 09:19:57 -0700
From: Kees Cook <kees@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nicolas Schier <nicolas@fjasle.eu>,
	Dmitry Vyukov <dvyukov@google.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	linux-kbuild@vger.kernel.org, linux-hardening@vger.kernel.org,
	kasan-dev@googlegroups.com, Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev
Subject: Re: [PATCH] gcc-plugins: Remove SANCOV plugin
Message-ID: <202504090919.6DE21CFA7A@keescook>
References: <20250409160251.work.914-kees@kernel.org>
 <32bb421a-1a9e-40eb-9318-d8ca1a0f407f@app.fastmail.com>
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In-Reply-To: <32bb421a-1a9e-40eb-9318-d8ca1a0f407f@app.fastmail.com>

On Wed, Apr 09, 2025 at 06:16:58PM +0200, Arnd Bergmann wrote:
> On Wed, Apr 9, 2025, at 18:02, Kees Cook wrote:
> > There are very few users of this plugin[1], and since it's features
> > are available in GCC 6 and later (and Clang), users can update their
> > compilers if they need support on newer kernels.
> >
> > Suggested-by: Arnd Bergmann <arnd@arndb.de>
> > Link: 
> > https://lore.kernel.org/all/08393aa3-05a3-4e3f-8004-f374a3ec4b7e@app.fastmail.com/ 
> > [1]
> > Signed-off-by: Kees Cook <kees@kernel.org>
> >
> > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> > index 1af972a92d06..e7347419ffc5 100644
> > --- a/lib/Kconfig.debug
> > +++ b/lib/Kconfig.debug
> > @@ -2135,15 +2135,13 @@ config ARCH_HAS_KCOV
> >  config CC_HAS_SANCOV_TRACE_PC
> >  	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
> > 
> 
> My version removed CC_HAS_SANCOV_TRACE_PC as well, as I planned
> to have this on top of my patch to require gcc-8.1 as the
> minimum version.
> 
> >  config KCOV
> >  	bool "Code coverage for fuzzing"
> >  	depends on ARCH_HAS_KCOV
> > -	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
> > +	depends on CC_HAS_SANCOV_TRACE_PC
> 
> So this dependency would also disappear. I think either way is fine.
> 
> The rest of the patch is again identical to my version.

Ah! How about you keep the patch as part of your gcc-8.1 clean up, then?
That seems more clear, etc.

-Kees

-- 
Kees Cook