Re: Error loading xdp program that worked with bpf_load

[Elerion <elerion1000@gmail.com>]

Hello here's some of the basic information, I don't have a minimum
code sample to reproduce the error and I don't really feel inclined to
spend the time to make one since I have already found a solution. I'm
not able to release the production code we are using.

5.3.0-53-generic #47~18.04.1-Ubuntu SMP Thu May 7 13:10:50 UTC 2020
x86_64 x86_64 x86_64 GNU/Linux
Ubuntu clang version
10.0.1-++20200529024103+a634a80615b-1~exp1~20200529124721.169
Target: x86_64-pc-linux-gnu

You can find the discussion here:

https://www.spinics.net/lists/xdp-newbies/msg01730.html

On Thu, Jun 11, 2020 at 1:46 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Thu, Jun 11, 2020 at 1:41 PM Elerion <elerion1000@gmail.com> wrote:
> >
> > I am using libbpf from here https://github.com/libbpf/libbpf I'm not
> > using ebpf. I just linked to the ebpf issue because it seems like the
> > only thing related to this problem when I googled it.
>
> Ok, that I can help with, then.
>
> What's the kernel version? Where I can find repro? Steps, etc.
> Basically, a bit more context would help, as I wasn't part of initial
> discussion.
>
>
> >
> > On Thu, Jun 11, 2020 at 9:34 AM Andrii Nakryiko
> > <andrii.nakryiko@gmail.com> wrote:
> > >
> > > On Thu, Jun 11, 2020 at 4:00 AM Jesper Dangaard Brouer
> > > <brouer@redhat.com> 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 <elerion1000@gmail.com> 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 <toke@redhat.com> wrote:
> > > > > >
> > > > > > Elerion <elerion1000@gmail.com> 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
> > > >