run ./xdp_pass_user --dev lo error! in Ubuntu 20.04

[alenliu]

1. My os version

root@ubuntu20-04:~/xdp-tutorial/basic01-xdp-pass# cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.5 LTS"

root@ubuntu20-04:~/xdp-tutorial/basic01-xdp-pass# uname -a
Linux ubuntu20-04 5.4.0-169-generic #187-Ubuntu SMP Thu Nov 23 14:52:28 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

2. My configure process

~/xdp-tutorial# ./configure 
clang: 11.0.0-2~ubuntu20.04.1
libbpf support: submodule
ELF support: yes
zlib support: yes
libxdp support: submodule
Configuring libxdp to use our libbpf submodule
Found clang binary 'clang' with version 11 (from 'Ubuntu clang version 11.0.0-2~ubuntu20.04.1')
not using emacs: 
using bpftool v7.3.0
libbpf support: custom v1.2.0
  perf_buffer__consume support: yes
  btf__load_from_kernel_by_id support: yes
  btf__type_cnt support: yes
  bpf_object__next_map support: yes
  bpf_object__next_program support: yes
  bpf_program__insn_cnt support: yes
  bpf_program__type support: yes
  bpf_program__flags support: yes
  bpf_program__expected_attach_type support: yes
  bpf_map_create support: yes
  perf_buffer__new_raw support: yes
  bpf_xdp_attach support: yes
  bpf_map__set_autocreate support: yes
  bpf_prog_test_run_opts support: yes
  bpf_xdp_query support: yes
zlib support: yes
ELF support: yes
pcap support: yes
secure_getenv support: yes

3. xdp_pass_user --dev lo error information

root@ubuntu20-04:~/xdp-tutorial/basic01-xdp-pass# ./xdp_pass_user --dev lo
libbpf: elf: skipping unrecognized data section(7) xdp_metadata
libbpf: prog 'xdp_pass': BPF program load failed: Invalid argument
libbpf: prog 'xdp_pass': failed to load: -22
libbpf: failed to load object 'xdp-dispatcher.o'
libbpf: elf: skipping unrecognized data section(7) xdp_metadata
libbpf: elf: skipping unrecognized data section(7) xdp_metadata
libbpf: elf: skipping unrecognized data section(7) xdp_metadata
libbpf: prog 'xdp_pass': BPF program load failed: Argument list too long
libbpf: prog 'xdp_pass': failed to load: -7
libbpf: failed to load object 'xdp-dispatcher.o'
libxdp: Compatibility check for dispatcher program failed: Argument list too long
libxdp: Falling back to loading single prog without dispatcher
libbpf: elf: skipping unrecognized data section(7) xdp_metadata
libbpf: prog 'xdp_pass': BPF program load failed: Invalid argument
libbpf: prog 'xdp_pass': failed to load: -22
libbpf: failed to load object 'xdp-dispatcher.o'
Success: Loading XDP prog name:xdp_prog_simple(id:48) on device:lo(ifindex:1)

Can anybody help me?

[tohojo]

alenliu ***@***.***> writes:

***@***.***:~/xdp-tutorial/basic01-xdp-pass# uname -a Linux ubuntu20-04 5.4.0-169-generic #187-Ubuntu SMP Thu Nov 23 14:52:28 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

A 5.4 kernel is too old to use the XDP dispatcher, so you can't attach multiple programs to a single interface...

Success: Loading XDP prog name:xdp_prog_simple(id:48) on device:lo(ifindex:1)

However, it looks like the fallback to loading a single program works, and you end up with the attachment working?

[daiminglong]

Hi, I have the same problem, but even though this happend, the example bpf code loaded successfully. My kernel version is 5.4, So if I just wanna to try single bpf program case, that means I can ignore this error msg? @tohojo

[root@VM-119-213-tencentos basic01-xdp-pass]# ls
Makefile README.org xdp_pass_kern.c xdp_pass_kern.ll xdp_pass_kern.o xdp_pass_user xdp_pass_user.c
[root@VM-119-213-tencentos basic01-xdp-pass]# ./xdp_pass_user --dev test
libbpf: elf: skipping unrecognized data section(7) xdp_metadata
libbpf: prog 'xdp_pass': BPF program load failed: Invalid argument
libbpf: prog 'xdp_pass': failed to load: -22
libbpf: failed to load object 'xdp-dispatcher.o'
libbpf: elf: skipping unrecognized data section(7) xdp_metadata
libbpf: elf: skipping unrecognized data section(7) xdp_metadata
libbpf: elf: skipping unrecognized data section(7) xdp_metadata
libbpf: prog 'xdp_pass': BPF program load failed: Argument list too long
libbpf: prog 'xdp_pass': failed to load: -7
libbpf: failed to load object 'xdp-dispatcher.o'
libxdp: Compatibility check for dispatcher program failed: Argument list too long
libxdp: Falling back to loading single prog without dispatcher
libbpf: elf: skipping unrecognized data section(7) xdp_metadata
libbpf: prog 'xdp_pass': BPF program load failed: Invalid argument
libbpf: prog 'xdp_pass': failed to load: -22
libbpf: failed to load object 'xdp-dispatcher.o'
Success: Loading XDP prog name:xdp_prog_simple(id:18) on device:test(ifindex:84)
[root@VM-119-213-tencentos basic01-xdp-pass]# xdp-loader status test
CURRENT XDP PROGRAM STATUS:

Interface Prio Program name Mode ID Tag Chain actions

test xdp_prog_simple native 18 3b185187f1855c4c

[tohojo]

Minglong Dai ***@***.***> writes:

Hi, I have the same problem, but even though this happend, the example bpf code loaded successfully. My kernel version is 5.4, So if I just wanna to try single bpf program case, that means I can ignore this error msg? @tohojo

Yup, that should be fine :)

[daiminglong]

Minglong Dai @.***> writes:
Hi, I have the same problem, but even though this happend, the example bpf code loaded successfully. My kernel version is 5.4, So if I just wanna to try single bpf program case, that means I can ignore this error msg? @tohojo
Yup, that should be fine :)

thks, It works