The patch titled
Subject: kbuild: enable -Wformat-truncation on clang
has been added to the -mm mm-nonmm-unstable branch. Its filename is
kbuild-enable-wformat-truncation-on-clang.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kbuild-enable-wformat-truncation-on-clang.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Arnd Bergmann <arnd@xxxxxxxx>
Subject: kbuild: enable -Wformat-truncation on clang
Date: Mon, 15 Apr 2024 14:20:35 +0200
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@xxxxxxxxxx/
Link: https://lkml.kernel.org/r/20240415122037.1983124-5-arnd@xxxxxxxxxx
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Nicolas Schier <nicolas@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
scripts/Makefile.extrawarn | 7 +++++++
1 file changed, 7 insertions(+)
--- a/scripts/Makefile.extrawarn~kbuild-enable-wformat-truncation-on-clang
+++ a/scripts/Makefile.extrawarn
@@ -100,7 +100,14 @@ KBUILD_CFLAGS += $(call cc-disable-warni
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
_
Patches currently in -mm which might be from arnd@xxxxxxxx are
fix-missing-vmalloch-includes-fix-5.patch
kcov-avoid-clang-out-of-range-warning.patch
test_hexdump-avoid-string-truncation-warning.patch
block-partitions-ldm-convert-strncpy-to-strscpy.patch
blktrace-convert-strncpy-to-strscpy_pad.patch
kbuild-turn-on-wextra-by-default.patch
kbuild-remove-redundant-extra-warning-flags.patch
kbuild-turn-on-wrestrict-by-default.patch
kbuild-enable-wformat-truncation-on-clang.patch
kbuild-enable-wcast-function-type-strict-unconditionally.patch
kbuild-enable-wstringop-truncation-globally.patch
