[ 1243.856589][T11137] Could not find device with ifindex 2000 in netnsfd 11
[ 1243.857409][T11137] Could not find netns with fd: 2000
[ 1243.857988][T11137] Cannot link a netdevsim to itself
[ 1243.858663][T11137] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).