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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Thu, 6 Jan 2022 09:40:17 -0800
Message-ID: <CAADnVQLjjcsckQVqaSB8ODB4FKdVUt-PB9xyJ3FAa2GWGLbHgA@mail.gmail.com>
Subject: Re: [RFC 00/13] kprobe/bpf: Add support to attach multiple kprobes
To:     Masami Hiramatsu <mhiramat@kernel.org>
Cc:     Jiri Olsa <jolsa@redhat.com>, Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>, lkml <linux-kernel@vger.kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
        "David S. Miller" <davem@davemloft.net>
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On Thu, Jan 6, 2022 at 5:59 AM Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> That seems to bind your mind. The program type is just a programing
> 'model' of the bpf. You can choose the best implementation to provide
> equal functionality. 'kprobe' in bpf is just a name that you call some
> instrumentations which can probe kernel code.

No. We're not going to call it "fprobe" or any other name.
From bpf user's pov it's going to be "multi attach kprobe",
because this is how everyone got to know kprobes.
The 99% usage is at the beginning of the funcs.
When users say "kprobe" they don't care how kernel attaches it.
The func entry limitation for "multi attach kprobe" is a no-brainer.

And we need both "multi attach kprobe" and "multi attach kretprobe"
at the same time. It's no go to implement one first and the other
some time later.