Yes I'm using tail-calls, and yes that's definitely the problem I was
thinking about. Gotta upgrade to 4.19 then. Thanks a lot for the fast
replies.
Il giorno mer 21 nov 2018 alle ore 11:52 Jesper Dangaard Brouer
<brouer@xxxxxxxxxx> ha scritto:
>
> On Wed, 21 Nov 2018 11:01:45 +0100
> Pavel Popa <pashinho1990@xxxxxxxxx> wrote:
>
> > For what I see, the only way to return -EFAULT is in this case
> > https://elixir.bootlin.com/linux/v4.18.10/source/net/core/filter.c#L3259.
> > This may explain the "to_ifindex=0" thing, as 'fwd' is initialized
> > NULL. But I don't understand the meaning of the
> > "xdp_map_invalid(xdp_prog, map_owner)" condition. So, if that's really
> > the case, what can be inferred from this?
>
> Are you using BPF-tail calls?
>
> Well that code got removed in kernel 4.19:
>
> Commit f6069b9aa993 ("bpf: fix redirect to map under tail calls")
> https://git.kernel.org/torvalds/c/f6069b9aa993
>
> --
> Best regards,
> Jesper Dangaard Brouer
> MSc.CS, Principal Kernel Engineer at Red Hat
> LinkedIn: http://www.linkedin.com/in/brouer
>
> $ git describe --contains f6069b9aa993
> v4.19-rc1~86^2~6^2
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