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From: John Fastabend <john.fastabend@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	Alexei Starovoitov <ast@fb.com>
Cc: John Fastabend <john.fastabend@gmail.com>,
	Andrii Nakryiko <andriin@fb.com>, bpf <bpf@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Kernel Team <Kernel-team@fb.com>
Subject: Re: [PATCH bpf-next 1/2] libbpf: stop enforcing kern_version, populate it for users
Date: Fri, 04 Oct 2019 08:59:30 -0700	[thread overview]
Message-ID: <5d976c62bb52b_583b2ae668e6e5b41@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <CAEf4BzbUSQdYqce+gyjO7-VSrF45nqXuLBMU6qRd63LHD+-JLg@mail.gmail.com>

Andrii Nakryiko wrote:
> On Fri, Oct 4, 2019 at 7:36 AM Alexei Starovoitov <ast@fb.com> wrote:
> >
> > On 10/4/19 7:32 AM, Andrii Nakryiko wrote:
> > >> If we are not going to validate the section should we also skip collect'ing it?
> > > Well, if user supplied version, we will parse and use it to override
> > > out prepopulated one, so in that sense we do have validation.
> > >
> > > But I think it's fine just to drop it altogether. Will do in v3.
> > >
> >
> > what about older kernel that still enforce it?
> > May be populate it in bpf_attr while loading, but
> > don't check it in elf from libbpf?
> 
> That's what my change does. I pre-populate correct kernel version in
> bpf_object->kern_version from uname(). If ELF has "version" section,
> we still parse it and override bpf_object->kern_version.
> bpf_object->kern_version then is always specified as part of
> bpf_prog_load->kern_version.
> 
> So what we are discussing here is to not even look at user-provided
> version, but just always specify correct current kernel version. So I
> don't think we are going to break anything, except we might allow to
> pass some programs that were failing before due to unspecified or zero
> version.
> 
> So with that, do you think it's ok to get rid of version section altogether?

Should be fine on my side. Go for it.

  reply	other threads:[~2019-10-04 15:59 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-04  3:00 [PATCH bpf-next 0/2] Add new-style bpf_object__open APIs Andrii Nakryiko
2019-10-04  3:00 ` [PATCH bpf-next 1/2] libbpf: stop enforcing kern_version, populate it for users Andrii Nakryiko
2019-10-04 14:05   ` John Fastabend
2019-10-04 14:32     ` Andrii Nakryiko
2019-10-04 14:36       ` Alexei Starovoitov
2019-10-04 14:55         ` John Fastabend
2019-10-04 15:07         ` Andrii Nakryiko
2019-10-04 15:59           ` John Fastabend [this message]
2019-10-18 14:49             ` John Fastabend
2019-10-04  3:00 ` [PATCH bpf-next 2/2] libbpf: add bpf_object__open_{file,mem} w/ extensible opts Andrii Nakryiko

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