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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

  reply	other threads:[~2023-05-30  1:39 UTC|newest]

Thread overview: 21+ 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 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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