Re: [PATCH] ubsan: integer-overflow: depend on BROKEN to keep this out of CI

[Eric Biggers <ebiggers@kernel.org>]

On Wed, May 28, 2025 at 11:26:22AM -0700, Kees Cook wrote:
> Depending on !COMPILE_TEST isn't sufficient to keep this feature out of
> CI because we can't stop it from being included in randconfig builds.
> This feature is still highly experimental, and is developed in lock-step
> with Clang's Overflow Behavior Types[1]. Depend on BROKEN to keep it
> from being enabled by anyone not expecting it.
> 
> Link: https://discourse.llvm.org/t/rfc-v2-clang-introduce-overflowbehaviortypes-for-wrapping-and-non-wrapping-arithmetic/86507 [1]
> Signed-off-by: Kees Cook <kees@kernel.org>
> ---
> Cc: Justin Stitt <justinstitt@google.com>
> Cc: Eric Biggers <ebiggers@kernel.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Jann Horn <jannh@google.com>
> Cc: Marco Elver <elver@google.com>
> Cc: llvm@lists.linux.dev
> Cc: <linux-hardening@vger.kernel.org>
> ---
>  lib/Kconfig.ubsan | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
> index f6ea0c5b5da3..96cd89668467 100644
> --- a/lib/Kconfig.ubsan
> +++ b/lib/Kconfig.ubsan
> @@ -118,6 +118,8 @@ config UBSAN_UNREACHABLE
>  
>  config UBSAN_INTEGER_WRAP
>  	bool "Perform checking for integer arithmetic wrap-around"
> +	# This is very experimental so drop the next line if you really want it
> +	depends on BROKEN
>  	depends on !COMPILE_TEST
>  	depends on $(cc-option,-fsanitize-undefined-ignore-overflow-pattern=all)
>  	depends on $(cc-option,-fsanitize=signed-integer-overflow)
> -- 

Acked-by: Eric Biggers <ebiggers@kernel.org>

- Eric