[ 1111.674861][T11115] Could not find device with ifindex 2000 in netnsfd 11 [ 1111.675652][T11115] Could not find netns with fd: 2000 [ 1111.676248][T11115] Cannot link a netdevsim to itself [ 1111.676977][T11115] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).