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Date:   Sun, 4 Oct 2020 00:10:45 -0700
From:   Nathan Chancellor <natechancellor@gmail.com>
To:     Kees Cook <keescook@chromium.org>
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 2/4] ubsan: Disable object-size sanitizer under GCC
Message-ID: <20201004071045.GB1650@Ryzen-9-3900X.localdomain>
References: <20201002221527.177500-1-keescook@chromium.org>
 <20201002221527.177500-3-keescook@chromium.org>
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On Fri, Oct 02, 2020 at 03:15:25PM -0700, Kees Cook wrote:
> GCC's -fsanitize=object-size (as part of CONFIG_UBSAN_MISC) greatly
> increases stack utilization. Do not allow this under GCC.
> 
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Link: https://lore.kernel.org/lkml/CAHk-=wjPasyJrDuwDnpHJS2TuQfExwe=px-SzLeN8GFMAQJPmQ@mail.gmail.com/

Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>

> ---
>  lib/Kconfig.ubsan | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
> index c0b801871e0b..aeb2cdea0b94 100644
> --- a/lib/Kconfig.ubsan
> +++ b/lib/Kconfig.ubsan
> @@ -104,6 +104,9 @@ config UBSAN_UNSIGNED_OVERFLOW
>  
>  config UBSAN_OBJECT_SIZE
>  	def_bool UBSAN_MISC
> +	# gcc hugely expands stack usage with -fsanitize=object-size
> +	# https://lore.kernel.org/lkml/CAHk-=wjPasyJrDuwDnpHJS2TuQfExwe=px-SzLeN8GFMAQJPmQ@mail.gmail.com/
> +	depends on !CC_IS_GCC
>  	depends on $(cc-option,-fsanitize=object-size)
>  
>  config UBSAN_BOOL
> -- 
> 2.25.1