Hi Gerald, FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant. tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: fd8dab197cca2746e1fcd399a218eec5164726d4 commit: 42deddf3ef5c23358e28758db7726fcc8d9c31ec [3174/4127] s390: select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP config: s390-randconfig-r044-20221030 compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 791a7ae1ba3efd6bca96338e10ffde557ba83920) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=42deddf3ef5c23358e28758db7726fcc8d9c31ec git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout 42deddf3ef5c23358e28758db7726fcc8d9c31ec # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot All errors (new ones prefixed by >>): >> mm/hugetlb_vmemmap.c:421:60: error: unexpected type name 'bool': expected identifier core_param(hugetlb_free_vmemmap, vmemmap_optimize_enabled, bool, 0); ^ >> mm/hugetlb_vmemmap.c:421:66: error: expected identifier core_param(hugetlb_free_vmemmap, vmemmap_optimize_enabled, bool, 0); ^ >> mm/hugetlb_vmemmap.c:421:1: error: type specifier missing, defaults to 'int'; ISO C99 and later do not support implicit int [-Wimplicit-int] core_param(hugetlb_free_vmemmap, vmemmap_optimize_enabled, bool, 0); ^ int >> mm/hugetlb_vmemmap.c:421:11: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes] core_param(hugetlb_free_vmemmap, vmemmap_optimize_enabled, bool, 0); ^ void 4 errors generated. Kconfig warnings: (for reference only) WARNING: unmet direct dependencies detected for VIDEO_MEDIATEK_VPU Depends on [n]: MEDIA_SUPPORT [=y] && MEDIA_PLATFORM_SUPPORT [=y] && MEDIA_PLATFORM_DRIVERS [=y] && V4L_MEM2MEM_DRIVERS [=n] && VIDEO_DEV [=m] && (ARCH_MEDIATEK || COMPILE_TEST [=y]) Selected by [m]: - VIDEO_MEDIATEK_MDP3 [=m] && MEDIA_SUPPORT [=y] && MEDIA_PLATFORM_SUPPORT [=y] && MEDIA_PLATFORM_DRIVERS [=y] && (MTK_IOMMU [=y] || COMPILE_TEST [=y]) && VIDEO_DEV [=m] && (ARCH_MEDIATEK || COMPILE_TEST [=y]) && HAS_DMA [=y] && REMOTEPROC [=y] vim +/bool +421 mm/hugetlb_vmemmap.c e9fdff87e893ec Muchun Song 2021-06-30 419 30152245c63b59 Muchun Song 2022-06-28 420 static bool vmemmap_optimize_enabled = IS_ENABLED(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON); 30152245c63b59 Muchun Song 2022-06-28 @421 core_param(hugetlb_free_vmemmap, vmemmap_optimize_enabled, bool, 0); f41f2ed43ca525 Muchun Song 2021-06-30 422 :::::: The code at line 421 was first introduced by commit :::::: 30152245c63b59f835193b37212991bc24669645 mm: hugetlb_vmemmap: replace early_param() with core_param() :::::: TO: Muchun Song :::::: CC: Andrew Morton -- 0-DAY CI Kernel Test Service https://01.org/lkp