[ 1231.228599][T11121] Could not find device with ifindex 2000 in netnsfd 11
[ 1231.229362][T11121] Could not find netns with fd: 2000
[ 1231.229941][T11121] Cannot link a netdevsim to itself
[ 1231.230679][T11121] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).