[ 1070.751147][T11102] Could not find device with ifindex 2000 in netnsfd 11 [ 1070.751896][T11102] Could not find netns with fd: 2000 [ 1070.752464][T11102] Cannot link a netdevsim to itself [ 1070.753138][T11102] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).