Re: [PATCH 12/43] kcsan: clang: retire CONFIG_KCSAN_KCOV_BROKEN

From: Alexander Potapenko <glider@google.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Marco Elver <elver@google.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andrey Konovalov <andreyknvl@google.com>,
	Andy Lutomirski <luto@kernel.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
	Christoph Hellwig <hch@lst.de>, Christoph Lameter <cl@linux.com>,
	David Rientjes <rientjes@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Eric Dumazet <edumazet@google.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Ilya Leoshkevich <iii@linux.ibm.com>,
	Ingo Molnar <mingo@redhat.com>, Jens Axboe <axboe@kernel.dk>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Kees Cook <keescook@chromium.org>,
	Matthew Wilcox <willy@infradead.org>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Pekka Enberg <penberg@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Petr Mladek <pmladek@suse.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Vegard Nossum <vegard.nossum@oracle.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Linux Memory Management List <linux-mm@kvack.org>,
	Linux-Arch <linux-arch@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 12/43] kcsan: clang: retire CONFIG_KCSAN_KCOV_BROKEN
Date: Fri, 18 Mar 2022 15:34:34 +0100	[thread overview]
Message-ID: <CAG_fn=U96hVmJxk17z+N8yFxxGABy4vE-FHJUGYNMZYbHG_hyg@mail.gmail.com> (raw)
In-Reply-To: <Ybn/DZb32ujokTnJ@FVFF77S0Q05N>

On Wed, Dec 15, 2021 at 3:43 PM Mark Rutland <mark.rutland@arm.com> wrote:
>
> On Wed, Dec 15, 2021 at 02:39:43PM +0100, Marco Elver wrote:
> > On Wed, 15 Dec 2021 at 14:33, Mark Rutland <mark.rutland@arm.com> wrote:
> > >
> > > On Tue, Dec 14, 2021 at 05:20:19PM +0100, Alexander Potapenko wrote:
> > > > kcov used to be broken prior to Clang 11, but right now that version is
> > > > already the minimum required to build with KCSAN, that is why we don't
> > > > need KCSAN_KCOV_BROKEN anymore.
> > >
> > > Just to check, how is that requirement enforced?
> >
> > HAVE_KCSAN_COMPILER will only be true with Clang 11 or later, due to
> > no prior compiler having "-tsan-distinguish-volatile=1".
>
> I see -- could we add wording to that effect into the commit messge?

Will be done.

> > > I see the core Makefiles enforce 10.0.1+, but I couldn't spot an explicit
> > > version dependency in Kconfig.kcsan.
> > >
> > > Otherwise, this looks good to me!
> >
> > I think 5.17 will be Clang 11 only, so we could actually revert
> > ea91a1d45d19469001a4955583187b0d75915759:
> > https://lkml.kernel.org/r/Yao86FeC2ybOobLO@archlinux-ax161
> >
> > I should resend that to be added to the -kbuild tree.
>
> FWIW, that also works for me.
>
> Thanks,
> Mark.

-- 
Alexander Potapenko
Software Engineer

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