[ 1253.740284][T11120] Could not find device with ifindex 2000 in netnsfd 11
[ 1253.741041][T11120] Could not find netns with fd: 2000
[ 1253.741607][T11120] Cannot link a netdevsim to itself
[ 1253.742340][T11120] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).