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From: Alexei Starovoitov <alexei.starovoitov@gmail•com>
To: Jesper Dangaard Brouer <brouer@redhat•com>
Cc: Daniel Borkmann <daniel@iogearbox•net>,
	netdev@vger•kernel.org, Daniel Borkmann <borkmann@iogearbox•net>
Subject: Re: [PATCH net-next] bpf: return errno -ENOMEM when exceeding RLIMIT_MEMLOCK
Date: Tue, 21 Feb 2017 00:06:11 -0800	[thread overview]
Message-ID: <20170221080609.GA42330@ast-mbp.thefacebook.com> (raw)
In-Reply-To: <20170220172558.3de0742d@redhat.com>

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 <daniel@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.
There is also code in iovisor/bcc that specifically looking
for EPERM to adjust ulimit.
May be it's not documented properly, but that's different story.

  reply	other threads:[~2017-02-21  8:06 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-20 15:35 [PATCH net-next] bpf: return errno -ENOMEM when exceeding RLIMIT_MEMLOCK Jesper Dangaard Brouer
2017-02-20 15:57 ` Daniel Borkmann
2017-02-20 16:25   ` Jesper Dangaard Brouer
2017-02-21  8:06     ` Alexei Starovoitov [this message]
2017-02-21 13:00       ` Jesper Dangaard Brouer
2017-02-22  7:14         ` Alexei Starovoitov

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