Re: net: deadlock between ip_expire/sch_direct_xmit

From	Paolo Abeni <pabeni@redhat.com>
Newsgroups	linux.kernel
Subject	Re: net: deadlock between ip_expire/sch_direct_xmit
Date	2017-03-14 16:40 +0100
Message-ID	<tkWIj-25L-41@gated-at.bofh.it> (permalink)
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On Tue, 2017-03-14 at 08:09 -0700, Eric Dumazet wrote:
> On Tue, Mar 14, 2017 at 8:03 AM, Paolo Abeni <pabeni@redhat.com> wrote:
> 
> > I'm wondering if we really need to keep the fragment queue lock held
> > while sending the icmp packet ? we hold a reference to the struct, so
> > it can't be deleted, and AFAICS after ipq_kill() nobody else could
> > access/modify that queue.
> > 
> > That lock is there pretty much forever, but perhaps is only a leftover
> > and we can release it just after ipq_kill() ?
> 
> Maybe, but for peace of mind I would make sure this code path owns the
> skb (head) before releasing the lock.
> 
> Seems something to try for net-next ?

Agreed.

I asked because I was in doubt I missed something obvious.

Thank you,

Paolo

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net: deadlock between ip_expire/sch_direct_xmit Dmitry Vyukov <dvyukov@google.com> - 2017-03-14 14:40 +0100
  Re: net: deadlock between ip_expire/sch_direct_xmit Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-14 15:50 +0100
    Re: net: deadlock between ip_expire/sch_direct_xmit Eric Dumazet <edumazet@google.com> - 2017-03-14 16:00 +0100
      Re: net: deadlock between ip_expire/sch_direct_xmit Dmitry Vyukov <dvyukov@google.com> - 2017-03-14 16:00 +0100
      Re: net: deadlock between ip_expire/sch_direct_xmit Cong Wang <xiyou.wangcong@gmail.com> - 2017-03-14 17:50 +0100
        Re: net: deadlock between ip_expire/sch_direct_xmit Dmitry Vyukov <dvyukov@google.com> - 2017-03-20 11:10 +0100
          Re: net: deadlock between ip_expire/sch_direct_xmit Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-20 13:50 +0100
    Re: net: deadlock between ip_expire/sch_direct_xmit Dmitry Vyukov <dvyukov@google.com> - 2017-03-14 16:00 +0100
    Re: net: deadlock between ip_expire/sch_direct_xmit Paolo Abeni <pabeni@redhat.com> - 2017-03-14 16:10 +0100
      Re: net: deadlock between ip_expire/sch_direct_xmit Eric Dumazet <edumazet@google.com> - 2017-03-14 16:20 +0100
        Re: net: deadlock between ip_expire/sch_direct_xmit Paolo Abeni <pabeni@redhat.com> - 2017-03-14 16:40 +0100

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