From: Yafang Shao <laoar.shao@gmail.com>
To: Jiri Olsa <olsajiri@gmail.com>
Cc: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com,
andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
yhs@fb.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, quentin@isovalent.com, bpf@vger.kernel.org
Subject: Re: [RFC PATCH bpf-next 1/8] bpf: Support ->show_fdinfo for kprobe_multi
Date: Tue, 30 May 2023 09:39:01 +0800 [thread overview]
Message-ID: <CALOAHbDTiPvawvS5xegiLVERzjh2MgmusDQFhCcfLY=wzw=oTA@mail.gmail.com> (raw)
In-Reply-To: <ZHSVSWph86bmJyvY@krava>
On Mon, May 29, 2023 at 8:06 PM Jiri Olsa <olsajiri@gmail.com> wrote:
>
> On Sun, May 28, 2023 at 02:20:20PM +0000, Yafang Shao wrote:
> > Currently, there is no way to check which functions are attached to a
> > kprobe_multi link, causing confusion for users. It is important that we
> > provide a means to expose these functions. The expected result is as follows,
> >
> > $ cat /proc/10936/fdinfo/9
> > pos: 0
> > flags: 02000000
> > mnt_id: 15
> > ino: 2094
> > link_type: kprobe_multi
> > link_id: 2
> > prog_tag: a04f5eef06a7f555
> > prog_id: 11
> > func_count: 4
> > func_addrs: ffffffffaad475c0
> > ffffffffaad47600
> > ffffffffaad47640
> > ffffffffaad47680
>
> I like the idea of exposing this through the link_info syscall,
> but I'm bit concerned of potentially dumping thousands of addresses
> through fdinfo file, because I always thought of fdinfo as brief
> file info, but that might be just my problem ;-)
In most cases, there are only a few addresses, and it is uncommon to
have thousands of addresses. To handle this, what about displaying a
maximum of 16 addresses? For cases where the number of addresses
exceeds 16, we can use '...' to represent the remaining addresses.
--
Regards
Yafang
next prev parent reply other threads:[~2023-05-30 1:39 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-28 14:20 [RFC PATCH bpf-next 0/8] bpf: Support ->show_fdinfo and ->fill_link_info for kprobe prog Yafang Shao
2023-05-28 14:20 ` [RFC PATCH bpf-next 1/8] bpf: Support ->show_fdinfo for kprobe_multi Yafang Shao
2023-05-29 12:06 ` Jiri Olsa
2023-05-30 1:39 ` Yafang Shao [this message]
2023-05-31 0:28 ` Alexei Starovoitov
2023-05-31 3:14 ` Yafang Shao
2023-05-28 14:20 ` [RFC PATCH bpf-next 2/8] bpf: Support ->fill_link_info " Yafang Shao
2023-05-29 2:44 ` kernel test robot
2023-05-30 1:42 ` Yafang Shao
2023-05-29 12:49 ` Jiri Olsa
2023-05-30 1:41 ` Yafang Shao
2023-05-28 14:20 ` [RFC PATCH bpf-next 3/8] bpftool: Show probed function in kprobe_multi link info Yafang Shao
2023-05-30 11:15 ` Quentin Monnet
2023-05-31 3:16 ` Yafang Shao
2023-05-31 0:31 ` Alexei Starovoitov
2023-05-31 3:17 ` Yafang Shao
2023-05-28 14:20 ` [RFC PATCH bpf-next 4/8] bpf: Always expose the probed address Yafang Shao
2023-05-28 14:20 ` [RFC PATCH bpf-next 5/8] bpf: Support ->show_fdinfo for perf_event Yafang Shao
2023-05-28 14:20 ` [RFC PATCH bpf-next 6/8] bpf: Add a common helper bpf_copy_to_user() Yafang Shao
2023-05-28 14:20 ` [RFC PATCH bpf-next 7/8] bpf: Support ->fill_link_info for perf_event Yafang Shao
2023-05-31 0:37 ` Alexei Starovoitov
2023-05-31 3:24 ` Yafang Shao
2023-05-28 14:20 ` [RFC PATCH bpf-next 8/8] bpftool: Show probed function in perf_event link info Yafang Shao
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