[ 1109.048485][T11118] Could not find device with ifindex 2000 in netnsfd 11 [ 1109.049222][T11118] Could not find netns with fd: 2000 [ 1109.049869][T11118] Cannot link a netdevsim to itself [ 1109.050535][T11118] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).