[  491.497758] Could not find device with ifindex 2000 in netnsfd 11
[  491.497906] Could not find netns with fd: 2000
[  491.497992] netdevsim netdevsim394 eth0: Cannot link a netdevsim to itself
[  491.498090] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).