On Tue, 21 Feb 2017 00:06:11 -0800
Alexei Starovoitov <alexei.starovoi...@gmail.com> wrote:
> On Mon, Feb 20, 2017 at 05:25:58PM +0100, Jesper Dangaard Brouer wrote:
> > On Mon, 20 Feb 2017 16:57:34 +0100
> > Daniel Borkmann <dan...@iogearbox.net> wrote:
> >
> > > On 02/20/2017 04:35 PM, Jesper Dangaard Brouer wrote:
> > > > It is confusing users of samples/bpf that exceeding the resource
> > > > limits for RLIMIT_MEMLOCK result in an "Operation not permitted"
> > > > message. This is due to bpf limits check return -EPERM.
> > > >
> > > > Instead return -ENOMEM, like most other users of this API.
> > > >
> > > > Fixes: aaac3ba95e4c ("bpf: charge user for creation of BPF maps and
> > > > programs")
> > > > Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements")
> > > > Fixes: 5ccb071e97fb ("bpf: fix overflow in prog accounting")
> > >
> > > Btw, last one just moves the helper so fixes doesn't really apply
> > > there, but apart from that this is already uapi exposed behavior
> > > like this for ~1.5yrs, so unfortunately too late to change now. I
> > > think the original intention (arguably confusing in this context)
> > > was that user doesn't have (rlimit) permission to allocate this
> > > resource.
> >
> > This is obviously confusing end-users, thus it should be fixed IMHO.
>
> I don't think it's confusing and I think EPERM makes
> the most sense as return code in such situation.
Most other kernel users return ENOMEM.
> There is also code in iovisor/bcc that specifically looking
> for EPERM to adjust ulimit.
If there is already a program that depend on this, then it is ABI and
we cannot change it... drop this patch.
> May be it's not documented properly, but that's different story.
Documented it here:
https://prototype-kernel.readthedocs.io/en/latest/bpf/troubleshooting.html
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
