Hello all, I tried to build the latest samples/bpf following instructions in the README.rst in samples/bpf folder. I ran into various issue such as: samples/bpf/Makefile:375: *** Cannot find a vmlinux for VMLINUX_BTF at any of " /home/szeng/dii-tools/linux/vmlinux", build the kernel or set VMLINUX_BTF or VMLINUX_H variable I was able to fix above issue by enable CONFIG_DEBUG_INFO_BTF in kernel .config file. But I eventually ran into other errors. I had to fix those errors by install dwarves, updating my clang/llvm to version 10. I was able to build it if I comment out all the xdp programs from Makefile. It seems those xdp programs require advanced features such as data structure layout in vmlinux.h (dumped from vmlinux using bpftool) and this require special kernel config support. So I thought instead of fixing those errors one by one, I should ask those who are working in this area, is there any instructions on how to build samples/bpf? The README.rst seems out-of-date, for example, it doesn't mention CONFIG_DEBUG_INFO_BTF. The required llvm/clang version in README.rst is also out-of-date. More specifically, to build samples/bpf, is there an example kernel .config to use? I tried those config here https://github.com/torvalds/linux/blob/master/tools/testing/selftests/bpf/config but build errors persist. Or is there any other tools I need to install/update on my system? My whole build log is as below: szeng@linux:~/dii-tools/linux$ make M=samples/bpf readelf: Error: Missing knowledge of 32-bit reloc types used in DWARF sections of machine number 247 readelf: Warning: unable to apply unsupported reloc type 10 to section .debug_info readelf: Warning: unable to apply unsupported reloc type 1 to section .debug_info readelf: Warning: unable to apply unsupported reloc type 10 to section .debug_info make -C /home/szeng/dii-tools/linux/samples/bpf/../../tools/lib/bpf RM='rm -rf' EXTRA_CFLAGS="-Wall -O2 -Wmissing-prototypes -Wstrict-prototypes -I./usr/include -I./tools/testing/selftests/bpf/ -I/home/szeng/dii-tools/linux/samples/bpf/libbpf/include -I./tools/include -I./tools/perf -DHAVE_ATTR_TEST=0" \ LDFLAGS= srctree=/home/szeng/dii-tools/linux/samples/bpf/../../ \ O= OUTPUT=/home/szeng/dii-tools/linux/samples/bpf/libbpf/ DESTDIR=/home/szeng/dii-tools/linux/samples/bpf/libbpf prefix= \ /home/szeng/dii-tools/linux/samples/bpf/libbpf/libbpf.a install_headers CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/libbpf.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/bpf.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/nlattr.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/btf.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/libbpf_errno.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/str_error.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/netlink.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/bpf_prog_linfo.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/libbpf_probes.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/xsk.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/hashmap.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/btf_dump.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/ringbuf.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/strset.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/linker.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/gen_loader.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/relo_core.o LD /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/libbpf-in.o LINK /home/szeng/dii-tools/linux/samples/bpf/libbpf/libbpf.a INSTALL headers CC samples/bpf/test_lru_dist CC samples/bpf/sock_example CC samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.o CC samples/bpf/../../tools/testing/selftests/bpf/trace_helpers.o CC samples/bpf/cookie_uid_helper_example.o CC samples/bpf/cpustat_user.o CC samples/bpf/fds_example.o CC samples/bpf/hbm.o CC samples/bpf/i915_latency_hist_user.o CC samples/bpf/i915_stat_user.o CC samples/bpf/ibumad_user.o CC samples/bpf/lathist_user.o CC samples/bpf/lwt_len_hist_user.o CC samples/bpf/map_perf_test_user.o CC samples/bpf/offwaketime_user.o CC samples/bpf/sampleip_user.o CC samples/bpf/sockex1_user.o CC samples/bpf/sockex2_user.o CC samples/bpf/sockex3_user.o CC samples/bpf/spintest_user.o CC samples/bpf/syscall_tp_user.o CC samples/bpf/task_fd_query_user.o CC samples/bpf/tc_l2_redirect_user.o CC samples/bpf/test_cgrp2_array_pin.o CC samples/bpf/test_cgrp2_attach.o CC samples/bpf/test_cgrp2_sock.o CC samples/bpf/test_cgrp2_sock2.o CC samples/bpf/test_current_task_under_cgroup_user.o CC samples/bpf/test_map_in_map_user.o CC samples/bpf/test_overhead_user.o CC samples/bpf/test_probe_write_user_user.o CC samples/bpf/trace_event_user.o CC samples/bpf/trace_output_user.o CC samples/bpf/tracex1_user.o CC samples/bpf/tracex2_user.o CC samples/bpf/tracex3_user.o CC samples/bpf/tracex4_user.o CC samples/bpf/tracex5_user.o CC samples/bpf/tracex6_user.o CC samples/bpf/tracex7_user.o CC samples/bpf/xdp1_user.o CC samples/bpf/xdp_adjust_tail_user.o CC samples/bpf/xdp_fwd_user.o make -C /home/szeng/dii-tools/linux/samples/bpf/../../tools/bpf/bpftool srctree=/home/szeng/dii-tools/linux/samples/bpf/../../ \ OUTPUT=/home/szeng/dii-tools/linux/samples/bpf/bpftool/ \ LIBBPF_OUTPUT=/home/szeng/dii-tools/linux/samples/bpf/libbpf/ \ LIBBPF_DESTDIR=/home/szeng/dii-tools/linux/samples/bpf/libbpf/ Auto-detecting system features: ... libbfd: [ OFF ] ... disassembler-four-args: [ OFF ] ... zlib: [ on ] ... libcap: [ OFF ] ... clang-bpf-co-re: [ on ] CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/libbpf.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/bpf.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/nlattr.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/btf.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/libbpf_errno.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/str_error.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/netlink.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/bpf_prog_linfo.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/libbpf_probes.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/xsk.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/hashmap.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/btf_dump.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/ringbuf.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/strset.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/linker.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/gen_loader.o CC /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/relo_core.o LD /home/szeng/dii-tools/linux/samples/bpf/libbpf/staticobjs/libbpf-in.o LINK /home/szeng/dii-tools/linux/samples/bpf/libbpf/libbpf.a CLANG /home/szeng/dii-tools/linux/samples/bpf/bpftool/profiler.bpf.o GEN /home/szeng/dii-tools/linux/samples/bpf/bpftool/profiler.skel.h CC /home/szeng/dii-tools/linux/samples/bpf/bpftool/prog.o CLANG /home/szeng/dii-tools/linux/samples/bpf/bpftool/pid_iter.bpf.o GEN /home/szeng/dii-tools/linux/samples/bpf/bpftool/pid_iter.skel.h CC /home/szeng/dii-tools/linux/samples/bpf/bpftool/pids.o LINK /home/szeng/dii-tools/linux/samples/bpf/bpftool/bpftool CC samples/bpf/xdp_router_ipv4_user.o CC samples/bpf/xdp_rxq_info_user.o CC samples/bpf/xdp_sample_pkts_user.o CC samples/bpf/xdp_tx_iptunnel_user.o CC samples/bpf/xdpsock_ctrl_proc.o CC samples/bpf/xsk_fwd.o CLANG-BPF samples/bpf/xdp_sample.bpf.o CLANG-BPF samples/bpf/xdp_redirect_map_multi.bpf.o CLANG-BPF samples/bpf/xdp_redirect_cpu.bpf.o CLANG-BPF samples/bpf/xdp_redirect_map.bpf.o CLANG-BPF samples/bpf/xdp_monitor.bpf.o CLANG-BPF samples/bpf/xdp_redirect.bpf.o BPF GEN-OBJ samples/bpf/xdp_monitor BPF GEN-SKEL samples/bpf/xdp_monitor libbpf: map 'rx_cnt': unexpected def kind var. Error: failed to open BPF object file: Invalid argument samples/bpf/Makefile:430: recipe for target 'samples/bpf/xdp_monitor.skel.h' failed make[1]: *** [samples/bpf/xdp_monitor.skel.h] Error 255 make[1]: *** Deleting file 'samples/bpf/xdp_monitor.skel.h' Makefile:1868: recipe for target 'samples/bpf' failed make: *** [samples/bpf] Error 2 Thanks, Oak
