[ 1081.566229][T11113] Could not find device with ifindex 2000 in netnsfd 11 [ 1081.566968][T11113] Could not find netns with fd: 2000 [ 1081.567551][T11113] Cannot link a netdevsim to itself [ 1081.568282][T11113] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).