CONFIG_WERROR turns warnings into errors, which happens only for *.c files because -Werror is added to KBUILD_CFLAGS. Adding it to KBUILD_CPPFLAGS makes more sense because preprocessors understand the -Werror option. For example, you can put a #warning directive in any preprocessed code. warning: #warning "this is a warning message" [-Wcpp] If -Werror is added, it is promoted to an error. error: #warning "this is a warning message" [-Werror=cpp] This commit moves -Werror to KBUILD_CPPFLAGS so it works in the same way for *.c, *.S, *.lds.S or whatever needs preprocessing. Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> --- Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/Makefile b/Makefile index 53fa1a9fba8a..f84b57910667 100644 --- a/Makefile +++ b/Makefile @@ -869,7 +869,8 @@ stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG) := -fstack-protector-strong KBUILD_CFLAGS += $(stackp-flags-y) -KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror +KBUILD_CPPFLAGS-$(CONFIG_WERROR) += -Werror +KBUILD_CPPFLAGS += $(KBUILD_CPPFLAGS-y) KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings -- 2.34.1