[ 1078.552070][T11128] Could not find device with ifindex 2000 in netnsfd 11 [ 1078.552743][T11128] Could not find netns with fd: 2000 [ 1078.553404][T11128] Cannot link a netdevsim to itself [ 1078.554060][T11128] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).