From f06e108a3dc53c0f5234d18de0bd224753db5019 Mon Sep 17 00:00:00 2001 From: Jan Hendrik Farr Date: Tue, 29 Oct 2024 15:00:36 +0100 Subject: Compiler Attributes: disable __counted_by for clang < 19.1.3 This patch disables __counted_by for clang versions < 19.1.3 because of the two issues listed below. It does this by introducing CONFIG_CC_HAS_COUNTED_BY. 1. clang < 19.1.2 has a bug that can lead to __bdos returning 0: https://github.com/llvm/llvm-project/pull/110497 2. clang < 19.1.3 has a bug that can lead to __bdos being off by 4: https://github.com/llvm/llvm-project/pull/112636 Fixes: c8248faf3ca2 ("Compiler Attributes: counted_by: Adjust name and identifier expansion") Cc: stable@vger.kernel.org # 6.6.x: 16c31dd7fdf6: Compiler Attributes: counted_by: bump min gcc version Cc: stable@vger.kernel.org # 6.6.x: 2993eb7a8d34: Compiler Attributes: counted_by: fixup clang URL Cc: stable@vger.kernel.org # 6.6.x: 231dc3f0c936: lkdtm/bugs: Improve warning message for compilers without counted_by support Cc: stable@vger.kernel.org # 6.6.x Reported-by: Nathan Chancellor Closes: https://lore.kernel.org/all/20240913164630.GA4091534@thelio-3990X/ Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202409260949.a1254989-oliver.sang@intel.com Link: https://lore.kernel.org/all/Zw8iawAF5W2uzGuh@archlinux/T/#m204c09f63c076586a02d194b87dffc7e81b8de7b Suggested-by: Nathan Chancellor Signed-off-by: Jan Hendrik Farr Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Reviewed-by: Miguel Ojeda Reviewed-by: Thorsten Blum Link: https://lore.kernel.org/r/20241029140036.577804-2-kernel@jfarr.cc Signed-off-by: Kees Cook --- init/Kconfig | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index 530a382ee0fe..92f106cf5572 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -116,6 +116,15 @@ config CC_HAS_ASM_INLINE config CC_HAS_NO_PROFILE_FN_ATTR def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) +config CC_HAS_COUNTED_BY + # TODO: when gcc 15 is released remove the build test and add + # a gcc version check + def_bool $(success,echo 'struct flex { int count; int array[] __attribute__((__counted_by__(count))); };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror) + # clang needs to be at least 19.1.3 to avoid __bdos miscalculations + # https://github.com/llvm/llvm-project/pull/110497 + # https://github.com/llvm/llvm-project/pull/112636 + depends on !(CC_IS_CLANG && CLANG_VERSION < 190103) + config PAHOLE_VERSION int default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE)) -- cgit v1.2.3-70-g09d2