reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/sean-jc/linux/commit/e68f0bf34a72fdda235204e06f90224903512e13
        git remote add sean-jc https://github.com/sean-jc/linux
        git fetch --no-tags sean-jc x86/mmu_follow_pfn
        git checkout e68f0bf34a72fdda235204e06f90224903512e13
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash arch/x86/kvm/