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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Nathan Chancellor <nathan@kernel.org>,
        Sami Tolvanen <samitolvanen@google.com>,
        Kees Cook <keescook@chromium.org>
Subject: [PATCH 4.14 020/210] Makefile.extrawarn: Move -Wcast-function-type-strict to W=1
Date:   Mon, 24 Oct 2022 13:28:57 +0200
Message-Id: <20221024112957.612369058@linuxfoundation.org>
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From: Sami Tolvanen <samitolvanen@google.com>

commit 2120635108b35ecad9c59c8b44f6cbdf4f98214e upstream.

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>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220930203310.4010564-1-samitolvanen@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 scripts/Makefile.extrawarn |    1 +
 1 file changed, 1 insertion(+)

--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -74,5 +74,6 @@ KBUILD_CFLAGS += $(call cc-disable-warni
 KBUILD_CFLAGS += $(call cc-disable-warning, uninitialized)
 KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)
 KBUILD_CFLAGS += $(call cc-disable-warning, unaligned-access)
+KBUILD_CFLAGS += $(call cc-disable-warning, cast-function-type-strict)
 endif
 endif