[ 1104.606000][T11108] Could not find device with ifindex 2000 in netnsfd 11 [ 1104.607109][T11108] Could not find netns with fd: 2000 [ 1104.608006][T11108] Cannot link a netdevsim to itself [ 1104.609124][T11108] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).