[ 1079.480911][T11100] Could not find device with ifindex 2000 in netnsfd 11 [ 1079.481964][T11100] Could not find netns with fd: 2000 [ 1079.482888][T11100] Cannot link a netdevsim to itself [ 1079.483998][T11100] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).