From: Yonghong Song <yhs@fb.com>
To: Song Liu <songliubraving@fb.com>
Cc: bpf <bpf@vger.kernel.org>, Networking <netdev@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Kernel Team <Kernel-team@fb.com>,
"john.fastabend@gmail.com" <john.fastabend@gmail.com>,
"kpsingh@chromium.org" <kpsingh@chromium.org>
Subject: Re: [PATCH v4 bpf-next 4/4] selftests/bpf: add bpf_iter test with bpf_get_task_stack()
Date: Mon, 29 Jun 2020 11:22:59 -0700 [thread overview]
Message-ID: <30cafbac-723b-c5a2-84aa-b9899d3c8997@fb.com> (raw)
In-Reply-To: <D3BAF0B3-122D-409C-B0DD-600E1EE606C0@fb.com>
On 6/29/20 9:56 AM, Song Liu wrote:
>
>
>> On Jun 29, 2020, at 8:06 AM, Yonghong Song <yhs@fb.com> wrote:
>>
>>
>>
>> On 6/28/20 10:55 PM, Song Liu wrote:
>>> The new test is similar to other bpf_iter tests. It dumps all
>>> /proc/<pid>/stack to a seq_file. Here is some example output:
>>> pid: 2873 num_entries: 3
>>> [<0>] worker_thread+0xc6/0x380
>>> [<0>] kthread+0x135/0x150
>>> [<0>] ret_from_fork+0x22/0x30
>>> pid: 2874 num_entries: 9
>>> [<0>] __bpf_get_stack+0x15e/0x250
>>> [<0>] bpf_prog_22a400774977bb30_dump_task_stack+0x4a/0xb3c
>>> [<0>] bpf_iter_run_prog+0x81/0x170
>>> [<0>] __task_seq_show+0x58/0x80
>>> [<0>] bpf_seq_read+0x1c3/0x3b0
>>> [<0>] vfs_read+0x9e/0x170
>>> [<0>] ksys_read+0xa7/0xe0
>>> [<0>] do_syscall_64+0x4c/0xa0
>>> [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>> Note: To print the output, it is necessary to modify the selftest.
>>
>> I do not know what this sentence means. It seems confusing
>> and probably not needed.
>
> It means current do_dummy_read() doesn't check/print the contents of the
> seq_file:
>
> /* not check contents, but ensure read() ends without error */
> while ((len = read(iter_fd, buf, sizeof(buf))) > 0)
> ;
I see. Thanks. It could be great if the commit message is more
explicit about what 'modify' is.
>>
>>> Signed-off-by: Song Liu <songliubraving@fb.com>
>>
>> Acked-by: Yonghong Song <yhs@fb.com>
>
> Thanks!
>
> [...]
>
next prev parent reply other threads:[~2020-06-29 19:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-29 5:55 [PATCH v4 bpf-next 0/4] bpf: introduce bpf_get_task_stack() Song Liu
2020-06-29 5:55 ` [PATCH v4 bpf-next 4/4] selftests/bpf: add bpf_iter test with bpf_get_task_stack() Song Liu
2020-06-29 15:06 ` Yonghong Song
2020-06-29 16:56 ` Song Liu
2020-06-29 18:22 ` Yonghong Song [this message]
2020-06-29 19:25 ` [PATCH v4 bpf-next 0/4] bpf: introduce bpf_get_task_stack() Andrii Nakryiko
[not found] ` <20200629055530.3244342-3-songliubraving@fb.com>
2020-06-30 4:18 ` [PATCH v4 bpf-next 2/4] bpf: introduce helper bpf_get_task_stack() Alexei Starovoitov
2020-06-30 6:12 ` Song Liu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=30cafbac-723b-c5a2-84aa-b9899d3c8997@fb.com \
--to=yhs@fb.com \
--cc=Kernel-team@fb.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=john.fastabend@gmail.com \
--cc=kpsingh@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=songliubraving@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).