From: Arnd Bergmann <arnd@kernel.org>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>,
Nicolas Schier <nicolas@fjasle.eu>,
linux-kbuild@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Nick Desaulniers <ndesaulniers@google.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Jani Nikula <jani.nikula@intel.com>,
Kees Cook <keescook@chromium.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: [PATCH 4/4] kbuild: enable -Wformat-truncation on clang
Date: Thu, 4 Apr 2024 17:16:57 +0200 [thread overview]
Message-ID: <20240404151713.3493098-5-arnd@kernel.org> (raw)
In-Reply-To: <20240404151713.3493098-1-arnd@kernel.org>
From: Arnd Bergmann <arnd@arndb.de>
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/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
| 7 +++++++
1 file changed, 7 insertions(+)
--git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index fbe4d7144860..5063b847a658 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -99,7 +99,14 @@ 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
--
2.39.2
next prev parent reply other threads:[~2024-04-04 15:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-04 15:16 [PATCH 0/4] Enable more warnings by default Arnd Bergmann
2024-04-04 15:16 ` [PATCH 1/4] kbuild: turn on -Wextra " Arnd Bergmann
2024-04-09 16:25 ` Nathan Chancellor
2024-04-09 18:42 ` Arnd Bergmann
2024-04-04 15:16 ` [PATCH 2/4] kbuild: remove redundant extra warning flags Arnd Bergmann
2024-04-04 15:16 ` [PATCH 3/4] kbuild: turn on -Wrestrict by default Arnd Bergmann
2024-04-04 15:16 ` Arnd Bergmann [this message]
2024-04-08 22:00 ` [PATCH 0/4] Enable more warnings " Justin Stitt
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