[ 1221.986090][T11120] Could not find device with ifindex 2000 in netnsfd 11
[ 1221.986824][T11120] Could not find netns with fd: 2000
[ 1221.987384][T11120] Cannot link a netdevsim to itself
[ 1221.988321][T11120] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).