[ 1074.886133][T11101] Could not find device with ifindex 2000 in netnsfd 11 [ 1074.886923][T11101] Could not find netns with fd: 2000 [ 1074.887548][T11101] Cannot link a netdevsim to itself [ 1074.888344][T11101] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).