The common error fount in forward-ported/backported patches is missing headers. One recent example (files and function names are mangled): void foo(){} EXPORT_SYMBOL(foo); gave only warning foo.c:12345678:5: warning: function declaration isn't a prototype [-Wstrict-prototypes] void foo(){} ^ foo.c:12345679:5: warning: data definition has no type or storage class [enabled by default] EXPORT_SYMBOL(foo); foo.c:12345679:5: warning: type defaults to 'int' in declaration of 'EXORT_SYMBOL' [-Werror=implicit-int] Now it's a fatal error. Tested on x86_64 allyesconfig. Signed-off-by: Sergei Trofimovich <slyfox@xxxxxxxxxx> Cc: Michal Marek <mmarek@xxxxxxx> Cc: linux-kbuild@xxxxxxxxxxxxxxx Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> --- Makefile | 6 +++++++ 1 file changed, 6 insertions(+) Change since v2: - moved CFLAGS checks lower to catch $(CROSS) case as suggested by Geert - added comments as other warning options do Change since v1: - use 'cc-option' to respect old gccs - fix typos. Thanks to Oleg Verych diff --git a/Makefile b/Makefile index a5a55f4..f5f36e1 100644 --- a/Makefile +++ b/Makefile @@ -659,6 +660,12 @@ KBUILD_CFLAGS += $(call cc-option,-fno-strict-overflow) # conserve stack if available KBUILD_CFLAGS += $(call cc-option,-fconserve-stack) +# disallog errors like 'EXPORT_GPL(foo);' with missing header +KBUILD_CFLAGS += $(call cc-option,-Werror=implicit-int) + +# require functions to have argumens in prototypes, not empty 'int foo()' +KBUILD_CFLAGS += $(call cc-option,-Werror=strict-prototypes) + # use the deterministic mode of AR if available KBUILD_ARFLAGS := $(call ar-option,D) -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html