/usr/src/linux-headers-4.4.0-38/include/rdma/ is in linux-headers-4.4.0-38 4.4.0-38.57.
This file is owned by root:root, with mode 0o755.
..
/usr/src/linux-headers-4.4.0-38/include/rdma/ib.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_addr.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_cache.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_cm.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_fmr_pool.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_mad.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_marshall.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_pack.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_pma.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_sa.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_smi.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_umem.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_umem_odp.h
/usr/src/linux-headers-4.4.0-38/include/rdma/ib_verbs.h
/usr/src/linux-headers-4.4.0-38/include/rdma/iw_cm.h
/usr/src/linux-headers-4.4.0-38/include/rdma/iw_portmap.h
/usr/src/linux-headers-4.4.0-38/include/rdma/opa_port_info.h
/usr/src/linux-headers-4.4.0-38/include/rdma/opa_smi.h
/usr/src/linux-headers-4.4.0-38/include/rdma/rdma_cm.h
/usr/src/linux-headers-4.4.0-38/include/rdma/rdma_cm_ib.h
/usr/src/linux-headers-4.4.0-38/include/rdma/rdma_netlink.h