Re: [PATCH v2] hardening: Avoid harmless Clang option under CONFIG_INIT_STACK_ALL_ZERO

On Tue, Sep 14, 2021 at 01:02:03PM -0700, Kees Cook wrote:

Currently under Clang, CC_HAS_AUTO_VAR_INIT_ZERO requires an extra
-enable flag compared to CC_HAS_AUTO_VAR_INIT_PATTERN. GCC does not,
and will happily ignore the Clang-specific flag. However, its presence
on the command-line is both cumbersome and confusing. Due to GCC's
tolerant behavior, though, we can continue to use a single Kconfig
cc-option test for the feature on both compilers, but then drop the
Clang-specific option in the Makefile.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: llvm@lists.linux.dev
Fixes: dcb7c0b9461c ("hardening: Clarify Kconfig text for auto-var-init")
Suggested-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/lkml/20210914102837.6172-1-will@kernel.org/ (local)
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <redacted>
---
 Makefile                   | 6 +++---
 security/Kconfig.hardening | 5 ++++-
 2 files changed, 7 insertions(+), 4 deletions(-)

Acked-by: Will Deacon <will@kernel.org>

Cheers for sorting this out!

Will