[  197.824492][ T1759] Could not find device with ifindex 2000 in netnsfd 11
[  197.825205][ T1759] Could not find netns with fd: 2000
[  197.825754][ T1759] Cannot link a netdevsim to itself
[  197.826450][ T1759] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).