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/bluetooth/bluetooth-next.git/commit/?id=251180e6dba54e9bc83b2e85680c536e7ae02219
        git remote add bluetooth-next https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git
        git fetch --no-tags bluetooth-next master
        git checkout 251180e6dba54e9bc83b2e85680c536e7ae02219
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm64 olddefconfig
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash dtbs_check