[ 1076.758585][T11098] Could not find device with ifindex 2000 in netnsfd 11 [ 1076.759616][T11098] Could not find netns with fd: 2000 [ 1076.760775][T11098] Cannot link a netdevsim to itself [ 1076.761891][T11098] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).