[  239.429486][ T3584] Could not find device with ifindex 2000 in netnsfd 11
[  239.430163][ T3584] Could not find netns with fd: 2000
[  239.430739][ T3584] Cannot link a netdevsim to itself
[  239.431409][ T3584] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).