Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
compiler_types: Disable __builtin_counted_by_ref for Clang
Unfortunately, there is a corner case of __builtin_counted_by_ref()
usage that crashes[1] Clang since support was introduced in Clang 19.
Disable it prior to Clang 22. Found while tested kmalloc_obj treewide
refactoring (via kmalloc_flex() usage).
Link: https://github.com/llvm/llvm-project/issues/182575 [1]
Signed-off-by: Kees Cook <kees@kernel.org>
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-1
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include/linux/compiler_types.h
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-1
include/linux/compiler_types.h
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* gcc: https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#index-_005f_005fbuiltin_005fcounted_005fby_005fref
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* clang: https://clang.llvm.org/docs/LanguageExtensions.html#builtin-counted-by-ref
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*/
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-
#if __has_builtin(__builtin_counted_by_ref)
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#if __has_builtin(__builtin_counted_by_ref) && \
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!defined(CONFIG_CC_HAS_BROKEN_COUNTED_BY_REF)
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/**
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* __flex_counter() - Get pointer to counter member for the given
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* flexible array, if it was annotated with __counted_by()
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init/Kconfig
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init/Kconfig
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# supported since gcc 16.0.0
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default y if CC_IS_GCC && GCC_VERSION >= 160000
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config CC_HAS_BROKEN_COUNTED_BY_REF
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bool
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# https://github.com/llvm/llvm-project/issues/182575
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default y if CC_IS_CLANG && CLANG_VERSION < 220000
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config CC_HAS_MULTIDIMENSIONAL_NONSTRING
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def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror)
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