From: Kees Cook <keescook@chromium.org>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ard Biesheuvel <ardb@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
Masahiro Yamada <masahiroy@kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
Nick Desaulniers <ndesaulniers@google.com>,
Marco Elver <elver@google.com>,
Randy Dunlap <rdunlap@infradead.org>,
Dmitry Vyukov <dvyukov@google.com>,
George Popescu <georgepope@android.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
Peter Oberparleiter <oberpar@linux.ibm.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] ubsan: Force -Wno-maybe-uninitialized only for GCC
Date: Mon, 5 Oct 2020 23:03:46 -0700 [thread overview]
Message-ID: <202010052301.CFBC03C72E@keescook> (raw)
In-Reply-To: <20201004071614.GC1650@Ryzen-9-3900X.localdomain>
On Sun, Oct 04, 2020 at 12:16:14AM -0700, Nathan Chancellor wrote:
> On Fri, Oct 02, 2020 at 03:15:26PM -0700, Kees Cook wrote:
> > Clang handles 'maybe-uninitialized' better in the face of using UBSAN,
> > so do not make this universally disabled for UBSAN builds.
> >
> > Signed-off-by: Kees Cook <keescook@chromium.org>
>
> Well this patch is not strictly necessary because Clang does not support
> -Wmaybe-uninitialized anyways :) its flags are -Wuninitialized and
> -Wsometimes-uninitialized so the warning stays enabled for UBSAN as it
> stands.
Ah, yes. Heh. Well... perhaps I can just drop this patch.
> However, something like this could still worthwhile because it would
> save us one call to cc-disable-warning (yay micro optimizations).
>
> Maybe it just does not need to have a whole new symbol, just make it
>
> ubsan-cflags-$(CONFIG_CC_IS_GCC)
>
> instead of
>
> ubsan-cflags-$(CONFIG_UBSAN)
If it gets kept, I'd still like it gated on CONFIG_UBSAN in some way
(e.g. the patch has an implicit depends due to the "if UBSAN" section).
But yes, this patch is rather a no-op.
--
Kees Cook
next prev parent reply other threads:[~2020-10-06 6:03 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-02 22:15 [PATCH 0/4] Clean up UBSAN Makefile Kees Cook
2020-10-02 22:15 ` [PATCH 1/4] ubsan: Move cc-option tests into Kconfig Kees Cook
2020-10-04 7:08 ` Nathan Chancellor
2020-10-06 6:01 ` Kees Cook
2020-10-02 22:15 ` [PATCH 2/4] ubsan: Disable object-size sanitizer under GCC Kees Cook
2020-10-04 7:10 ` Nathan Chancellor
2020-10-02 22:15 ` [PATCH 3/4] ubsan: Force -Wno-maybe-uninitialized only for GCC Kees Cook
2020-10-04 7:16 ` Nathan Chancellor
2020-10-06 6:03 ` Kees Cook [this message]
2020-10-02 22:15 ` [PATCH 4/4] ubsan: Disable UBSAN_TRAP for all*config Kees Cook
2020-10-04 7:16 ` Nathan Chancellor
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