[ 1110.664563][T11119] Could not find device with ifindex 2000 in netnsfd 11 [ 1110.665303][T11119] Could not find netns with fd: 2000 [ 1110.665890][T11119] Cannot link a netdevsim to itself [ 1110.666885][T11119] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).