reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/ceph/ceph-client/commit/8a1cb95e58001067ea33908f1762ca31d6f93b69
        git remote add ceph-client https://github.com/ceph/ceph-client.git
        git fetch --no-tags ceph-client binary_tracing
        git checkout 8a1cb95e58001067ea33908f1762ca31d6f93b69
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm olddefconfig
        ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash net/ceph/