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From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Song Liu <songliubraving@fb.com>
Cc: open list <linux-kernel@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>, Networking <netdev@vger.kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Kernel Team <Kernel-team@fb.com>,
	john fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	Daniel Xu <dlxu@fb.com>
Subject: Re: [PATCH bpf-next 2/5] libbpf: support BPF_PROG_TYPE_USER programs
Date: Tue, 4 Aug 2020 18:38:28 -0700	[thread overview]
Message-ID: <CAEf4BzYojfFiMn6VeUkxUsdSTdFK0A4MzKQxhCCp_OowkseznQ@mail.gmail.com> (raw)
In-Reply-To: <9C1285C1-ECD6-46BD-BA95-3E9E81C00EF0@fb.com>

On Mon, Aug 3, 2020 at 6:18 PM Song Liu <songliubraving@fb.com> wrote:
>
>
>
> > On Aug 2, 2020, at 6:40 PM, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
> >
> > On Sat, Aug 1, 2020 at 1:50 AM Song Liu <songliubraving@fb.com> wrote:
> >>
>
> [...]
>
> >
> >> };
> >>
> >> LIBBPF_API int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr);
> >> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> >> index b9f11f854985b..9ce175a486214 100644
> >> --- a/tools/lib/bpf/libbpf.c
> >> +++ b/tools/lib/bpf/libbpf.c
> >> @@ -6922,6 +6922,7 @@ static const struct bpf_sec_def section_defs[] = {
> >>        BPF_PROG_SEC("lwt_out",                 BPF_PROG_TYPE_LWT_OUT),
> >>        BPF_PROG_SEC("lwt_xmit",                BPF_PROG_TYPE_LWT_XMIT),
> >>        BPF_PROG_SEC("lwt_seg6local",           BPF_PROG_TYPE_LWT_SEG6LOCAL),
> >> +       BPF_PROG_SEC("user",                    BPF_PROG_TYPE_USER),
> >
> > let's do "user/" for consistency with most other prog types (and nice
> > separation between prog type and custom user name)
>
> About "user" vs. "user/", I still think "user" is better.
>
> Unlike kprobe and tracepoint, user prog doesn't use the part after "/".
> This is similar to "perf_event" for BPF_PROG_TYPE_PERF_EVENT, "xdl" for
> BPF_PROG_TYPE_XDP, etc. If we specify "user" here, "user/" and "user/xxx"
> would also work. However, if we specify "user/" here, programs that used
> "user" by accident will fail to load, with a message like:
>
>         libbpf: failed to load program 'user'
>
> which is confusing.

xdp, perf_event and a bunch of others don't enforce it, that's true,
they are a bit of a legacy, unfortunately. But all the recent ones do,
and we explicitly did that for xdp_dev/xdp_cpu, for instance.
Specifying just "user" in the spec would allow something nonsensical
like "userargh", for instance, due to this being treated as a prefix.
There is no harm to require users to do "user/my_prog", though.

Alternatively, we could introduce a new convention in the spec,
something like "user?", which would accept either "user" or
"user/something", but not "user/" nor "userblah". We can try that as
well.

>
> Thanks,
> Song
>
> [...]
>

  reply	other threads:[~2020-08-05  1:38 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-01  8:47 [PATCH bpf-next 0/5] introduce BPF_PROG_TYPE_USER Song Liu
2020-08-01  8:47 ` [PATCH bpf-next 1/5] bpf: " Song Liu
2020-08-01 13:58   ` kernel test robot
2020-08-01 15:21   ` kernel test robot
2020-08-06 18:18   ` kernel test robot
2020-08-06 18:18   ` [RFC PATCH] bpf: user_verifier_ops can be static kernel test robot
2020-08-01  8:47 ` [PATCH bpf-next 2/5] libbpf: support BPF_PROG_TYPE_USER programs Song Liu
2020-08-03  1:40   ` Andrii Nakryiko
2020-08-03  4:21     ` Song Liu
2020-08-03  5:05       ` Andrii Nakryiko
2020-08-04  1:18     ` Song Liu
2020-08-05  1:38       ` Andrii Nakryiko [this message]
2020-08-05  3:59         ` Song Liu
2020-08-05  5:32           ` Andrii Nakryiko
2020-08-05  6:26             ` Song Liu
2020-08-05  6:54               ` Andrii Nakryiko
2020-08-05  7:23                 ` Song Liu
2020-08-05 17:44                   ` Andrii Nakryiko
2020-08-01  8:47 ` [PATCH bpf-next 3/5] selftests/bpf: add selftest for BPF_PROG_TYPE_USER Song Liu
2020-08-03  1:43   ` Andrii Nakryiko
2020-08-03  4:33     ` Song Liu
2020-08-03  5:07       ` Andrii Nakryiko
2020-08-01  8:47 ` [PATCH bpf-next 4/5] selftests/bpf: move two functions to test_progs.c Song Liu
2020-08-03  1:46   ` Andrii Nakryiko
2020-08-03  4:34     ` Song Liu
2020-08-01  8:47 ` [PATCH bpf-next 5/5] selftests/bpf: add benchmark for uprobe vs. user_prog Song Liu
2020-08-03  1:51   ` Andrii Nakryiko
2020-08-03  4:47     ` Song Liu
2020-08-03  5:10       ` Andrii Nakryiko
2020-08-04 20:54         ` Song Liu
2020-08-05  1:52           ` Andrii Nakryiko
2020-08-05  4:47             ` Song Liu
2020-08-05  5:47               ` Andrii Nakryiko
2020-08-05  7:01                 ` Song Liu
2020-08-05 17:39                   ` Andrii Nakryiko
2020-08-05 18:41                     ` Song Liu
2020-08-05 17:16               ` Alexei Starovoitov
2020-08-05 17:27                 ` Andrii Nakryiko
2020-08-05 17:45                   ` Alexei Starovoitov
2020-08-05 17:56                     ` Andrii Nakryiko
2020-08-05 18:56                 ` Song Liu
2020-08-05 22:50                   ` Alexei Starovoitov
2020-08-05 23:50                     ` Song Liu

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