From: Cong Wang <xiyou.wangcong@gmail.com>
To: Gao Feng <gfree.wind@vip.163.com>
Cc: xeb@mail.ru, David Miller <davem@davemloft.net>,
Linux Kernel Network Developers <netdev@vger.kernel.org>
Subject: Re: Re: Re:Re: Re: [PATCH net] ppp: Fix a scheduling-while-atomic bug in del_chan
Date: Wed, 9 Aug 2017 11:18:44 -0700 [thread overview]
Message-ID: <CAM_iQpU3hx-Y7OXTDWARFc08BE6qQ_cEjZb7ciVKrWPFh2j0JA@mail.gmail.com> (raw)
In-Reply-To: <73e6ac77.45ea.15dc569d56a.Coremail.gfree.wind@vip.163.com>
On Tue, Aug 8, 2017 at 10:13 PM, Gao Feng <gfree.wind@vip.163.com> wrote:
> Maybe I didn't show my explanation clearly.
> I think it won't happen as I mentioned in the last email.
> Because the pptp_release invokes the synchronize_rcu to make sure it, and actually there is no one which would invoke del_chan except pptp_release.
> It is guaranteed by that the pptp_release doesn't put the sock refcnt until complete all cleanup include marking sk_state as PPPOX_DEAD.
>
> In other words, even though the pptp_release is not the last user of this sock, the other one wouldn't invoke del_chan in pptp_sock_destruct.
> Because the condition "!(sk->sk_state & PPPOX_DEAD)" must be false.
Only if sock->sk is always non-NULL for pptp_release(), which
is what I am not sure. If you look at other ->release(), similar checks
are there too, so not just for pptp.
>
> As summary, the del_chan and pppox_unbind_sock in pptp_sock_destruct are unnecessary.
> And it even brings confusing.
Sorry, I can't draw any conclusion for this.
next prev parent reply other threads:[~2017-08-09 18:19 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-31 10:07 [PATCH net] ppp: Fix a scheduling-while-atomic bug in del_chan gfree.wind
2017-08-01 4:59 ` David Miller
2017-08-01 20:39 ` Cong Wang
2017-08-02 17:13 ` Cong Wang
2017-08-07 1:32 ` Gao Feng
2017-08-07 17:17 ` Cong Wang
2017-08-07 17:34 ` Cong Wang
[not found] ` <697dbbd.7911.15dbf5ca3a6.Coremail.gfree.wind@vip.163.com>
2017-08-08 1:10 ` Gao Feng
2017-08-08 19:45 ` Cong Wang
2017-08-09 5:13 ` Gao Feng
2017-08-09 7:17 ` Gao Feng
2017-08-09 21:00 ` Cong Wang
2017-08-10 2:41 ` Gao Feng
2017-08-09 18:18 ` Cong Wang [this message]
2017-08-10 1:25 ` Re:Re: " Gao Feng
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