On Wed, 7 Nov 2018 13:00:09 -0800, Stanislav Fomichev wrote:
- }
- if (attr.prog_type == BPF_PROG_TYPE_FLOW_DISSECTOR) {
err = build_flow_dissector_jmp_table(obj, prog, "jmp_table");if (err) {p_err("failed to build flow dissector jump table");goto err_close_obj;}/* flow dissector consist of multiple programs,* we want to pin them allWhy pin them all shouldn't the main program be the only one pinned?
If I pin only the main program, the tail ones disappear from the jmp_table map when bpftool exits. Am I missing something? Should BPF_MAP_TYPE_PROG_ARRAY hold the referenced progs?
It does.
# bpftool map create /sys/fs/bpf/map \ type prog_array key 4 value 4 entries 4 \ name tail_call_map # bpftool prog load perf_event_output_stack.o /sys/fs/bpf/prog \ type xdp # bpftool map update pinned /sys/fs/bpf/map \ key 0 0 0 0 \ value pinned /sys/fs/bpf/prog # bpftool prog 11: xdp name xdp_prog1 tag 6f1b482b27443edf gpl loaded_at 2018-11-07T13:09:20-0800 uid 0 xlated 144B jited 130B memlock 4096B map_ids 14 # rm /sys/fs/bpf/prog # bpftool prog 11: xdp name xdp_prog1 tag 6f1b482b27443edf gpl loaded_at 2018-11-07T13:09:20-0800 uid 0 xlated 144B jited 130B memlock 4096B map_ids 14 # rm /sys/fs/bpf/map # bpftool prog # bpftool prog show id 11 Error: get by id (11): No such file or directory
I think we should remove all this auto tail call construction unless we have solid annotations in the elf file which can clearly guide the loader.