reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/commit/?id=aefcca2d0875add24036512e1f45bb9da89989c0
        git remote add vbabka https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git
        git fetch --no-tags vbabka DONTTEST-pcp-locking-bench
        git checkout aefcca2d0875add24036512e1f45bb9da89989c0
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash