reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        git checkout 5be63fc19fcaa4c236b307420483578a56986a37
        b4 shazam https://lore.kernel.org/r/20240905-patches-below_hint_mmap-v3-1-3cd5564efbbb@rivosinc.com
        # 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 mm/