From: Jesper Dangaard Brouer <brouer@redhat.com>
To: "Toke Høiland-Jørgensen" <toke@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
netdev@vger.kernel.org, bpf@vger.kernel.org, brouer@redhat.com
Subject: Re: [PATCH bpf-next] libbpf: Print hint about ulimit when getting permission denied error
Date: Mon, 16 Dec 2019 14:52:30 +0100 [thread overview]
Message-ID: <20191216145230.103c1f46@carbon> (raw)
In-Reply-To: <20191216124031.371482-1-toke@redhat.com>
On Mon, 16 Dec 2019 13:40:31 +0100
Toke Høiland-Jørgensen <toke@redhat.com> wrote:
> Probably the single most common error newcomers to XDP are stumped by is
> the 'permission denied' error they get when trying to load their program
> and 'ulimit -r' is set too low. For examples, see [0], [1].
>
> Since the error code is UAPI, we can't change that. Instead, this patch
> adds a few heuristics in libbpf and outputs an additional hint if they are
> met: If an EPERM is returned on map create or program load, and geteuid()
> shows we are root, and the current RLIMIT_MEMLOCK is not infinity, we
> output a hint about raising 'ulimit -r' as an additional log line.
>
> [0] https://marc.info/?l=xdp-newbies&m=157043612505624&w=2
> [1] https://github.com/xdp-project/xdp-tutorial/issues/86
>
> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
This is the top #1 issue users hit again-and-again, too bad we cannot
change the return code as it is UAPI now. Thanks for taking care of
this mitigation.
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2019-12-16 13:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-16 12:40 [PATCH bpf-next] libbpf: Print hint about ulimit when getting permission denied error Toke Høiland-Jørgensen
2019-12-16 13:52 ` Jesper Dangaard Brouer [this message]
2019-12-16 15:53 ` Daniel Borkmann
2019-12-16 16:00 ` Alexei Starovoitov
2019-12-16 16:11 ` Toke Høiland-Jørgensen
2019-12-16 16:08 ` Toke Høiland-Jørgensen
2019-12-16 16:51 ` Yonghong Song
2019-12-16 18:00 ` Toke Høiland-Jørgensen
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