[ 1114.278623][T11106] Could not find device with ifindex 2000 in netnsfd 11 [ 1114.279353][T11106] Could not find netns with fd: 2000 [ 1114.279955][T11106] Cannot link a netdevsim to itself [ 1114.310415][T11106] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).