Groups > linux.kernel > #1572076

Re: net: suspicious RCU usage in nf_hook

From	Eric Dumazet <edumazet@google.com>
Newsgroups	linux.kernel
Subject	Re: net: suspicious RCU usage in nf_hook
Date	2017-02-02 00:50 +0100
Message-ID	<t6cP0-4om-21@gated-at.bofh.it> (permalink)
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On Wed, Feb 1, 2017 at 3:29 PM, Cong Wang <xiyou.wangcong@gmail.com> wrote:

> Not sure if it is better. The difference is caught up in net_enable_timestamp(),
> which is called setsockopt() path and sk_clone() path, so we could be
> in netstamp_needed state for a long time too until user-space exercises
> these paths.
>
> I am feeling we probably need to get rid of netstamp_needed_deferred,
> and simply defer the whole static_key_slow_dec(), like the attached patch
> (compile only).
>
> What do you think?

I think we need to keep the atomic.

If two cpus call net_disable_timestamp() roughly at the same time, the
work will be scheduled once.

Thread

Re: net: suspicious RCU usage in nf_hook Cong Wang <xiyou.wangcong@gmail.com> - 2017-01-31 07:30 +0100
  Re: net: suspicious RCU usage in nf_hook Eric Dumazet <eric.dumazet@gmail.com> - 2017-01-31 16:50 +0100
    Re: net: suspicious RCU usage in nf_hook Cong Wang <xiyou.wangcong@gmail.com> - 2017-02-01 22:00 +0100
      Re: net: suspicious RCU usage in nf_hook Eric Dumazet <eric.dumazet@gmail.com> - 2017-02-01 22:20 +0100
        Re: net: suspicious RCU usage in nf_hook Eric Dumazet <eric.dumazet@gmail.com> - 2017-02-01 22:30 +0100
        Re: net: suspicious RCU usage in nf_hook Cong Wang <xiyou.wangcong@gmail.com> - 2017-02-02 00:40 +0100
          Re: net: suspicious RCU usage in nf_hook Eric Dumazet <edumazet@google.com> - 2017-02-02 00:50 +0100
            Re: net: suspicious RCU usage in nf_hook Eric Dumazet <eric.dumazet@gmail.com> - 2017-02-02 01:00 +0100
              Re: net: suspicious RCU usage in nf_hook Cong Wang <xiyou.wangcong@gmail.com> - 2017-02-02 19:10 +0100

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