reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/leon/linux-rdma.git/commit/?id=44ec5c9fb7ae5b9f5ac6c4a770797057224ac3e3
        git remote add leon-rdma https://git.kernel.org/pub/scm/linux/kernel/git/leon/linux-rdma.git
        git fetch --no-tags leon-rdma move-drivers
        git checkout 44ec5c9fb7ae5b9f5ac6c4a770797057224ac3e3
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/infiniband/hw/mlx5/