Re: [PATCH bpf-next v4 0/6] bpf: BTF support for ksyms

[Hao Luo]

Ah, this is the bug in pahole described in
https://lkml.org/lkml/2020/8/20/1862. I proposed a fix [1] but it
hasn't reached pahole's master branch. Let me ask Arnaldo to see if he
is OK merging it.

[1] https://www.spinics.net/lists/dwarves/msg00451.html

On Tue, Sep 29, 2020 at 9:36 PM Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
>
> On Tue, Sep 29, 2020 at 4:50 PM Hao Luo <haoluo@xxxxxxxxxx> wrote:
> >
> > v3 -> v4:
> >  - Rebasing
> >  - Cast bpf_[per|this]_cpu_ptr's parameter to void __percpu * before
> >    passing into per_cpu_ptr.
>
> Looks good, but doesn't work:
> ./test_progs -t ksyms_btf
> test_ksyms_btf:PASS:kallsyms_fopen 0 nsec
> test_ksyms_btf:PASS:ksym_find 0 nsec
> test_ksyms_btf:PASS:kallsyms_fopen 0 nsec
> test_ksyms_btf:PASS:ksym_find 0 nsec
> test_ksyms_btf:PASS:btf_exists 0 nsec
> libbpf: extern (ksym) 'bpf_prog_active': incompatible types, expected
> [4] int int, but kernel has [18729] var bpf_user_rnd_state
> libbpf: failed to load object 'test_ksyms_btf'
> libbpf: failed to load BPF skeleton 'test_ksyms_btf': -22
> test_ksyms_btf:FAIL:skel_open failed to open and load skeleton
> #43 ksyms_btf:FAIL
>
> I have the latest pahole from master. Any ideas?