[ 1222.620605][T11121] Could not find device with ifindex 2000 in netnsfd 11
[ 1222.621338][T11121] Could not find netns with fd: 2000
[ 1222.621930][T11121] Cannot link a netdevsim to itself
[ 1222.622634][T11121] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).