Commit 908dd508 authored Apr 15, 2024 by Arnd Bergmann Committed by Andrew Morton May 19, 2024

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>

parent 06bb7fc0

scripts/Makefile.extrawarn

+7 −0

Original line number	Diff line number	Diff line
		@@ -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