From: David Ahern <dsahern@gmail.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Eric Dumazet <eric.dumazet@gmail.com>,
"David S. Miller" <davem@davemloft.net>
Cc: Julian Anastasov <ja@ssi.bg>,
Cong Wang <xiyou.wangcong@gmail.com>,
syzbot <syzbot+30209ea299c09d8785c9@syzkaller.appspotmail.com>,
ddstreet@ieee.org, dvyukov@google.com,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
syzkaller-bugs@googlegroups.com
Subject: Re: unregister_netdevice: waiting for DEV to become free (2)
Date: Wed, 1 May 2019 08:52:37 -0600 [thread overview]
Message-ID: <70be7d61-a6fe-e703-978a-d17f544efb44@gmail.com> (raw)
In-Reply-To: <117fcc49-d389-c389-918f-86ccaef82e51@i-love.sakura.ne.jp>
On 5/1/19 7:38 AM, Tetsuo Handa wrote:
> On 2019/04/30 3:43, David Ahern wrote:
>>> The attached patch adds a tracepoint to notifier_call_chain. If you have
>>> KALLSYMS enabled it will show the order of the function handlers:
>>>
>>> perf record -e notifier:* -a -g &
>>>
>>> ip netns del <NAME>
>>> <wait a few seconds>
>>>
>>> fg
>>> <ctrl-c on perf-record>
>>>
>>> perf script
>>>
>>
>> with the header file this time.
>>
>
> What is the intent of your patch? I can see that many notifiers are called. But
> how does this help identify which event is responsible for dropping the refcount?
>
In a previous response you stated: "Since I'm not a netdev person, I
appreciate if you can explain that shutdown sequence using a flow chart."
The notifier sequence tells you the order of cleanup handlers and what
happens when a namespace is destroyed.
The dev_hold / dev_put tracepoint helps find the refcnt leak but
requires some time analyzing the output to match up hold / put stack traces.
next prev parent reply other threads:[~2019-05-01 14:52 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <00000000000056268e05737dcb95@google.com>
[not found] ` <000000000000c5b63005737f290d@google.com>
2018-08-15 20:41 ` unregister_netdevice: waiting for DEV to become free (2) Dmitry Vyukov
2018-08-20 4:31 ` syzbot
2018-08-20 12:55 ` Julian Anastasov
2018-08-21 5:40 ` Cong Wang
2018-08-22 4:11 ` Julian Anastasov
2019-04-15 13:36 ` Tetsuo Handa
2019-04-15 15:35 ` David Ahern
2019-04-21 20:41 ` Stephen Suryaputra
2019-04-22 14:58 ` David Ahern
2019-04-22 16:04 ` Eric Dumazet
2019-04-22 16:09 ` Eric Dumazet
2019-04-16 14:00 ` Tetsuo Handa
2019-04-26 13:43 ` Tetsuo Handa
2019-04-27 17:16 ` David Ahern
2019-04-27 22:33 ` Tetsuo Handa
2019-04-27 23:52 ` Eric Dumazet
2019-04-28 4:22 ` Tetsuo Handa
2019-04-28 15:04 ` Eric Dumazet
2019-04-29 18:34 ` David Ahern
2019-04-29 18:43 ` David Ahern
2019-05-01 13:38 ` Tetsuo Handa
2019-05-01 14:52 ` David Ahern [this message]
2019-05-01 16:16 ` Tetsuo Handa
2019-05-04 14:52 ` [PATCH] ipv4: Delete uncached routes upon unregistration of loopback device Tetsuo Handa
2019-05-04 15:56 ` Eric Dumazet
2019-05-04 17:09 ` Tetsuo Handa
2019-05-04 17:24 ` Eric Dumazet
2019-05-04 20:13 ` Julian Anastasov
2019-11-28 9:56 ` unregister_netdevice: waiting for DEV to become free (2) Tetsuo Handa
2019-11-29 5:54 ` Lukas Bulwahn
2019-11-29 6:51 ` Jouni Högander
2019-12-05 10:00 ` Jouni Högander
2019-12-05 11:00 ` Tetsuo Handa
2019-12-16 11:12 ` Tetsuo Handa
2019-12-17 7:08 ` Jouni Högander
2019-10-11 10:14 ` Tetsuo Handa
2019-10-11 15:12 ` Alexei Starovoitov
2019-10-16 10:34 ` Toke Høiland-Jørgensen
2019-11-15 9:43 ` Tetsuo Handa
2019-11-21 11:36 ` Toke Høiland-Jørgensen
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