Re: 'perf test BPF' failing, libbpf regression wrt "basic API for BPF obj name"

[Martin KaFai Lau]

On Tue, Nov 28, 2017 at 04:05:19PM -0300, Arnaldo Carvalho de Melo wrote:
> 
> [root@jouet ~]# perf test -v bpf
> 39: BPF filter                                            :
> 39.1: Basic BPF filtering                                 :
> --- start ---
> test child forked, pid 12198
> Kernel build dir is set to /lib/modules/4.14.0+/build
> set env: KBUILD_DIR=/lib/modules/4.14.0+/build
[ ... ]
> libbpf: failed to create map (name: 'flip_table'): Invalid argument
> libbpf: failed to load object '[basic_bpf_test]'
> bpf: load objects failed
88cda1c9da02 ("bpf: libbpf: Provide basic API support to specify BPF obj name")
is introduced in 4.15.

I think the perf@xxxxxxxxxxx broke on older kernels like 4.14 because
the new bpf prog/map name is only introduced since 4.15.

The newer perf needs to be compatible with an older kernel?