Re: Error loading xdp program that worked with bpf_load

On Thu, Jun 11, 2020 at 4:00 AM Jesper Dangaard Brouer
<[email protected]> wrote:
>
> (Cross-posting to iovisor-dev)
>
> Seeking input from BPF-llvm developers. How come Clang/LLVM 10+ is
> generating incompatible BTF-info in ELF file, and downgrading to LLVM-9
> fixes the issue ?
>
>
> On Wed, 10 Jun 2020 14:50:27 -0700 Elerion <[email protected]> wrote:
>
> > Never mind, I fixed it by downgrading to Clang 9.
> >
> > It appears to be an issue with Clang/LLVM 10+
> >
> > https://github.com/cilium/ebpf/issues/43

This is newer Clang recording that function is global, not static.
libbpf is sanitizing BTF to remove this flag, if kernel doesn't
support this. But given this is re-implementation of libbpf, that's
probably not happening, right?

> >
> > On Wed, Jun 10, 2020 at 2:38 PM Toke Høiland-Jørgensen <[email protected]> wrote:
> > >
> > > Elerion <[email protected]> writes:
> > >
> > > > [69] FUNC xdp_program type_id=68 vlen != 0
> > >
> > > 'vlen != 0' is the error. Not sure why you hit that; what's the output
> > > of 'bpftool btf dump file yourprog.o' ?
> > >
> > > -Toke
> > >
>
>
> --
> Best regards,
>   Jesper Dangaard Brouer
>   MSc.CS, Principal Kernel Engineer at Red Hat
>   LinkedIn: http://www.linkedin.com/in/brouer
>