[ 1215.410206][T11118] Could not find device with ifindex 2000 in netnsfd 11 [ 1215.410907][T11118] Could not find netns with fd: 2000 [ 1215.411673][T11118] Cannot link a netdevsim to itself [ 1215.412318][T11118] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).