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From: Quentin Monnet <quentin@isovalent.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: "Toke Høiland-Jørgensen" <toke@redhat.com>,
	"Arnaldo Carvalho de Melo" <acme@kernel.org>,
	"Alexei Starovoitov" <alexei.starovoitov@gmail.com>,
	"Andrii Nakryiko" <andriin@fb.com>, bpf <bpf@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>,
	"Alexei Starovoitov" <ast@fb.com>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Kernel Team" <kernel-team@fb.com>, "Hao Luo" <haoluo@google.com>,
	"Song Liu" <songliubraving@fb.com>
Subject: Re: [RFC PATCH bpf-next 8/8] tools/bpftool: show PIDs with FDs open against BPF map/prog/link/btf
Date: Mon, 15 Jun 2020 10:30:26 +0100	[thread overview]
Message-ID: <d2220bfb-db28-251a-66ca-6f3a6377c94f@isovalent.com> (raw)
In-Reply-To: <87pna01yzh.fsf@toke.dk>

2020-06-15 11:04 UTC+0200 ~ Toke Høiland-Jørgensen <toke@redhat.com>
> Arnaldo Carvalho de Melo <acme@kernel.org> writes:
> 
>> Em Fri, Jun 12, 2020 at 10:57:59PM -0700, Andrii Nakryiko escreveu:
>>> On Fri, Jun 12, 2020 at 8:45 PM Alexei Starovoitov
>>> <alexei.starovoitov@gmail.com> wrote:
>>>>
>>>> On Fri, Jun 12, 2020 at 03:31:50PM -0700, Andrii Nakryiko wrote:
>>>>> Add bpf_iter-based way to find all the processes that hold open FDs against
>>>>> BPF object (map, prog, link, btf). Add new flag (-o, for "ownership", given
>>>>> -p is already taken) to trigger collection and output of these PIDs.
>>>>>
>>>>> Sample output for each of 4 BPF objects:
>>>>>
>>>>> $ sudo ./bpftool -o prog show
>>>>> 1992: cgroup_skb  name egress_alt  tag 9ad187367cf2b9e8  gpl
>>>>>         loaded_at 2020-06-12T14:18:10-0700  uid 0
>>>>>         xlated 48B  jited 59B  memlock 4096B  map_ids 2074
>>>>>         btf_id 460
>>>>>         pids: 913709,913732,913733,913734
>>>>> 2062: cgroup_device  tag 8c42dee26e8cd4c2  gpl
>>>>>         loaded_at 2020-06-12T14:37:52-0700  uid 0
>>>>>         xlated 648B  jited 409B  memlock 4096B
>>>>>         pids: 1
>>>>>
>>>>> $ sudo ./bpftool -o map show
>>>>> 2074: array  name test_cgr.bss  flags 0x400
>>>>>         key 4B  value 8B  max_entries 1  memlock 8192B
>>>>>         btf_id 460
>>>>>         pids: 913709,913732,913733,913734
>>>>>
>>>>> $ sudo ./bpftool -o link show
>>>>> 82: cgroup  prog 1992
>>>>>         cgroup_id 0  attach_type egress
>>>>>         pids: 913709,913732,913733,913734
>>>>> 86: cgroup  prog 1992
>>>>>         cgroup_id 0  attach_type egress
>>>>>         pids: 913709,913732,913733,913734
>>>>
>>>> This is awesome.
>>
>> Indeed.
>>  
>>> Thanks.
>>>
>>>>
>>>> Why extra flag though? I think it's so useful that everyone would want to see
>>
>> Agreed.
>>  
>>> No good reason apart from "being safe by default". If turned on by
>>> default, bpftool would need to probe for bpf_iter support first. I can
>>> add probing and do this by default.
>>
>> I think this is the way to go.
> 
> +1
> 
> And also +1 on the awesomeness of this feature! :)
> 
> -Toke
> 

Thanks a lot Andrii, the feature looks great indeed.

Thank you for the clean-up and refactoring in bpftool and its Makefile
as well, I am happy to confirm that test_bpftool_build.sh still passes
on my setup with your changes.

Quentin

      reply	other threads:[~2020-06-15  9:30 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-12 22:31 [RFC PATCH bpf-next 0/8] libbpf ksym support and bpftool show PIDs Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 1/8] libbpf: generalize libbpf externs support Andrii Nakryiko
     [not found]   ` <CA+khW7hAYVdoQX5-j0z1iGEVZeww4BBu4NXzy5eS5OwDRYqe2w@mail.gmail.com>
2020-06-15 18:55     ` Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 2/8] libbpf: add support for extracting kernel symbol addresses Andrii Nakryiko
     [not found]   ` <CA+khW7hFZzp_K_xydSFw0O3LYB22_fC=Z4wG7i9Si+phGHn4cQ@mail.gmail.com>
2020-06-15 19:08     ` Andrii Nakryiko
2020-06-16  8:05       ` Hao Luo
2020-06-17  1:24         ` Hao Luo
2020-06-17  1:36           ` Andrii Nakryiko
2020-06-18  7:53             ` Hao Luo
2020-06-12 22:31 ` [RFC PATCH bpf-next 3/8] selftests/bpf: add __ksym extern selftest Andrii Nakryiko
     [not found]   ` <CA+khW7jxdS1KRpk2syVGjDqbyn3wAd3Eh_LEMAEhkPUehuXMwg@mail.gmail.com>
2020-06-15 19:11     ` Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 4/8] tools/bpftool: move map/prog parsing logic into common Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 5/8] tools/bpftool: minimize bootstrap bpftool Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 6/8] tools/bpftool: generalize BPF skeleton support and generate vmlinux.h Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 7/8] libbpf: wrap source argument of BPF_CORE_READ macro in parentheses Andrii Nakryiko
2020-06-12 22:31 ` [RFC PATCH bpf-next 8/8] tools/bpftool: show PIDs with FDs open against BPF map/prog/link/btf Andrii Nakryiko
2020-06-13  3:45   ` Alexei Starovoitov
2020-06-13  5:57     ` Andrii Nakryiko
2020-06-13 22:14       ` Arnaldo Carvalho de Melo
2020-06-15  9:04         ` Toke Høiland-Jørgensen
2020-06-15  9:30           ` Quentin Monnet [this message]

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