/usr/x86_64-linux-gnu/include/rdma/ is in linux-libc-dev-amd64-cross 4.15.0-18.19cross1.
This file is owned by root:root, with mode 0o755.
..
/usr/x86_64-linux-gnu/include/rdma/bnxt_re-abi.h
/usr/x86_64-linux-gnu/include/rdma/cxgb3-abi.h
/usr/x86_64-linux-gnu/include/rdma/cxgb4-abi.h
/usr/x86_64-linux-gnu/include/rdma/hfi/
/usr/x86_64-linux-gnu/include/rdma/hfi/hfi1_ioctl.h
/usr/x86_64-linux-gnu/include/rdma/hfi/hfi1_user.h
/usr/x86_64-linux-gnu/include/rdma/hns-abi.h
/usr/x86_64-linux-gnu/include/rdma/ib_user_cm.h
/usr/x86_64-linux-gnu/include/rdma/ib_user_ioctl_verbs.h
/usr/x86_64-linux-gnu/include/rdma/ib_user_mad.h
/usr/x86_64-linux-gnu/include/rdma/ib_user_sa.h
/usr/x86_64-linux-gnu/include/rdma/ib_user_verbs.h
/usr/x86_64-linux-gnu/include/rdma/mlx4-abi.h
/usr/x86_64-linux-gnu/include/rdma/mlx5-abi.h
/usr/x86_64-linux-gnu/include/rdma/mthca-abi.h
/usr/x86_64-linux-gnu/include/rdma/nes-abi.h
/usr/x86_64-linux-gnu/include/rdma/ocrdma-abi.h
/usr/x86_64-linux-gnu/include/rdma/qedr-abi.h
/usr/x86_64-linux-gnu/include/rdma/rdma_netlink.h
/usr/x86_64-linux-gnu/include/rdma/rdma_user_cm.h
/usr/x86_64-linux-gnu/include/rdma/rdma_user_ioctl.h
/usr/x86_64-linux-gnu/include/rdma/rdma_user_rxe.h
/usr/x86_64-linux-gnu/include/rdma/vmw_pvrdma-abi.h