[ 1220.466667][T11127] Could not find device with ifindex 2000 in netnsfd 11
[ 1220.467567][T11127] Could not find netns with fd: 2000
[ 1220.468133][T11127] Cannot link a netdevsim to itself
[ 1220.468889][T11127] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).