From 908dd508276da13a9b50c208577365d26692eb43 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann <arnd@arndb.de> Date: Mon, 15 Apr 2024 14:20:35 +0200 Subject: [PATCH] kbuild: enable -Wformat-truncation on clang This warning option still produces output on gcc but is now clean when building with clang, so enable it conditionally on the compiler for now. As far as I can tell, the remaining warnings with gcc are the result of analysing the code more deeply across inlining, while clang only does this within a function. Link: https://lore.kernel.org/lkml/20240326230511.GA2796782@dev-arch.thelio-3990X/ Link: https://lore.kernel.org/linux-patches/20231002-disable-wformat-truncation-overflow-non-kprintf-v1-1-35179205c8d9@kernel.org/ Link: https://lkml.kernel.org/r/20240415122037.1983124-5-arnd@kernel.org Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Kees Cook <keescook@chromium.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nicolas Schier <nicolas@fjasle.eu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- scripts/Makefile.extrawarn | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 95466a04d51bd..202e26e6f29fc 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -100,7 +100,14 @@ KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable) KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable) KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned) KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow) +ifdef CONFIG_CC_IS_GCC KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation) +else +# Clang checks for overflow/truncation with '%p', while GCC does not: +# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111219 +KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow-non-kprintf) +KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation-non-kprintf) +endif KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation) KBUILD_CFLAGS += -Wno-override-init # alias for -Wno-initializer-overrides in clang -- GitLab