[ 1081.958908][T11111] Could not find device with ifindex 2000 in netnsfd 11 [ 1081.959712][T11111] Could not find netns with fd: 2000 [ 1081.960259][T11111] Cannot link a netdevsim to itself [ 1081.960926][T11111] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).