On Thu, May 12, 2022 at 5:49 PM Vincent Li <vincent.mc.li@xxxxxxxxx> wrote:
>
> Hi,
>
> I cloned the bpf-next and tried to compile the bpf selftest.
>
> first I got error
>
> "
> CC /usr/src/bpf
> next/tools/testing/selftests/bpf/tools/build/bpftool/xlated_dumper.o
>
> make[1]: *** No rule to make target
> '/usr/src/bpf-next/tools/include/asm-generic/bitops/find.h', needed by
> '/usr/src/bpf-next/tools/testing/selftests/bpf/tools/build/bpftool/btf_dumper.o'.
> Stop.
>
> I could not find find.h in
> /usr/src/bpf-next/tools/include/asm-generic/bitops/find.h but I found
> it in /usr/src/bpf-next/tools/include/linux/find.h, copied it to
> /usr/src/bpf-next/tools/include/asm-generic/bitops, seems resolved the
> problem,
>
> then I got another error below,
>
> CLNG-BPF [test_maps] map_kptr.o
>
> progs/map_kptr.c:7:29: error: unknown attribute 'btf_type_tag' ignored
> [-Werror,-Wunknown-attributes]
>
> struct prog_test_ref_kfunc __kptr *unref_ptr;
>
> ^~~~~~
>
> /usr/src/bpf-next/tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:176:31:
> note: expanded from macro '__kptr'
>
> #define __kptr __attribute__((btf_type_tag("kptr")))
>
> ^~~~~~~~~~~~~~~~~~~~
>
> progs/map_kptr.c:8:29: error: unknown attribute 'btf_type_tag' ignored
> [-Werror,-Wunknown-attributes]
>
> struct prog_test_ref_kfunc __kptr_ref *ref_ptr;
>
> ^~~~~~~~~~
>
> /usr/src/bpf-next/tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:177:35:
> note: expanded from macro '__kptr_ref'
>
> #define __kptr_ref __attribute__((btf_type_tag("kptr_ref")))
> "
>
> my clang is 12.0.1 and installed new clang from llvm github repository
>
> clang version 15.0.0 (https://github.com/llvm/llvm-project.git
> e91a73de24d60954700d7ac0293c050ab2cbe90b)
>
> it resolved the problem, but now I got error
>
> GEN-SKEL [test_progs] test_bpf_nf.skel.h
>
> libbpf: failed to find BTF info for global/extern symbol 'bpf_skb_ct_lookup'
>
> Error: failed to link
> '/usr/src/bpf-next/tools/testing/selftests/bpf/test_bpf_nf.o': Unknown
> error -2 (-2)
>
> make: *** [Makefile:508:
> /usr/src/bpf-next/tools/testing/selftests/bpf/test_bpf_nf.skel.h]
> Error 254
>
> running out of ideas on how to fix the compiling error. I hope I am
> not doing something wrong :)
I recompiled the bpf-next kernel tree after clang 15 installation with
make bzImage; make modules; make and then recompiled bpf selftest, all
compiling errors are gone, sorry for the noise.
