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Date:   Fri, 30 Sep 2022 20:33:10 +0000
Mime-Version: 1.0
Message-ID: <20220930203310.4010564-1-samitolvanen@google.com>
Subject: [PATCH] Makefile.extrawarn: Move -Wcast-function-type-strict to W=1
From:   Sami Tolvanen <samitolvanen@google.com>
To:     Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>
Cc:     Nick Desaulniers <ndesaulniers@google.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Tom Rix <trix@redhat.com>, linux-kbuild@vger.kernel.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        Kees Cook <keescook@chromium.org>,
        Sami Tolvanen <samitolvanen@google.com>, stable@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

We enable -Wcast-function-type globally in the kernel to warn about
mismatching types in function pointer casts. Compilers currently
warn only about ABI incompability with this flag, but Clang 16 will
enable a stricter version of the check by default that checks for an
exact type match. This will be very noisy in the kernel, so disable
-Wcast-function-type-strict without W=1 until the new warnings have
been addressed.

Cc: stable@vger.kernel.org
Link: https://reviews.llvm.org/D134831
Link: https://github.com/ClangBuiltLinux/linux/issues/1724
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 scripts/Makefile.extrawarn | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 6ae482158bc4..52bd7df84fd6 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -64,6 +64,7 @@ KBUILD_CFLAGS += -Wno-sign-compare
 KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)
 KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare
 KBUILD_CFLAGS += $(call cc-disable-warning, unaligned-access)
+KBUILD_CFLAGS += $(call cc-disable-warning, cast-function-type-strict)
 endif
 
 endif

base-commit: 7bc6e90d7aa4170039abe80b9f4e8c8e4eb35091
-- 
2.38.0.rc1.362.ged0d419d3c-goog