After an innocuous change in -next that modified a structure that contains __counted_by, clang-19 start crashing when building certain files in drivers/gpu/drm/xe. When assertions are enabled, the more descriptive failure is:
clang: clang/lib/AST/RecordLayoutBuilder.cpp:3335: const ASTRecordLayout &clang::ASTContext::getASTRecordLayout(const RecordDecl *) const: Assertion `D && "Cannot get layout of forward declarations!"' failed. According to a reverse bisect, a tangential change to the LLVM IR generation phase of clang during the LLVM 20 development cycle [1] resolves this problem. Bump the version of clang that enables CONFIG_CC_HAS_COUNTED_BY to 20.1.0 to ensure that this issue cannot be hit. Link: https://github.com/llvm/llvm-project/commit/160fb1121cdf703c3ef5e61fb26c5659eb581489 [1] Signed-off-by: Nathan Chancellor <[email protected]> --- Should this be marked for stable? If this makes 6.17 final, I think we are fine for mainline and newer but I wonder if a patch that adds __counted_by to a structure would ever be backported and expose this problem there. --- init/Kconfig | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index af4c2f085455..a2675ee1ef8c 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -117,10 +117,11 @@ config CC_HAS_NO_PROFILE_FN_ATTR config CC_HAS_COUNTED_BY bool - # clang needs to be at least 19.1.3 to avoid __bdos miscalculations - # https://github.com/llvm/llvm-project/pull/110497 - # https://github.com/llvm/llvm-project/pull/112636 - default y if CC_IS_CLANG && CLANG_VERSION >= 190103 + # clang needs to be at least 20.1.0 to avoid potential crashes + # when building structures that contain __counted_by + # https://github.com/ClangBuiltLinux/linux/issues/2114 + # https://github.com/llvm/llvm-project/commit/160fb1121cdf703c3ef5e61fb26c5659eb581489 + default y if CC_IS_CLANG && CLANG_VERSION >= 200100 # supported since gcc 15.1.0 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896 default y if CC_IS_GCC && GCC_VERSION >= 150100 --- base-commit: f627b51aaa041cba715b59026cf2d9cb1476c7ed change-id: 20250807-fix-counted_by-clang-19-470d53f93aa0 Best regards, -- Nathan Chancellor <[email protected]>
