[ 1079.352997][T11096] Could not find device with ifindex 2000 in netnsfd 11 [ 1079.353743][T11096] Could not find netns with fd: 2000 [ 1079.354350][T11096] Cannot link a netdevsim to itself [ 1079.355055][T11096] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).