[ 1220.717831][T11123] Could not find device with ifindex 2000 in netnsfd 11
[ 1220.718526][T11123] Could not find netns with fd: 2000
[ 1220.719356][T11123] Cannot link a netdevsim to itself
[ 1220.720064][T11123] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).