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From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: xiyou.wangcong@gmail.com, edumazet@google.com,
	dvyukov@google.com, netdev@vger.kernel.org
Subject: Re: [PATCH net] net: use a work queue to defer net_disable_timestamp() work
Date: Fri, 03 Feb 2017 16:18:16 -0500 (EST)	[thread overview]
Message-ID: <20170203.161816.1608140108344194361.davem@davemloft.net> (raw)
In-Reply-To: <1486060295.21871.19.camel@edumazet-glaptop3.roam.corp.google.com>

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 02 Feb 2017 10:31:35 -0800

> From: Eric Dumazet <edumazet@google.com>
> 
> Dmitry reported a warning [1] showing that we were calling 
> net_disable_timestamp() -> static_key_slow_dec() from a non
> process context.
> 
> Grabbing a mutex while holding a spinlock or rcu_read_lock()
> is not allowed.
> 
> As Cong suggested, we now use a work queue.
> 
> It is possible netstamp_clear() exits while netstamp_needed_deferred
> is not zero, but it is probably not worth trying to do better than that.
> 
> netstamp_needed_deferred atomic tracks the exact number of deferred
> decrements.
 ...
> Fixes: b90e5794c5bd ("net: dont call jump_label_dec from irq context")
> Suggested-by: Cong Wang <xiyou.wangcong@gmail.com>
> Reported-by: Dmitry Vyukov <dvyukov@google.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Applied and queued up for -stable, thanks Eric.

      reply	other threads:[~2017-02-03 21:18 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-27 21:15 net: suspicious RCU usage in nf_hook Dmitry Vyukov
2017-01-27 23:22 ` Cong Wang
2017-01-27 23:30   ` Cong Wang
2017-01-27 23:35 ` Eric Dumazet
2017-01-28  1:00   ` Cong Wang
2017-01-28  1:31     ` Eric Dumazet
2017-01-31  6:19       ` Cong Wang
2017-01-31 15:44         ` Eric Dumazet
2017-02-01 20:51           ` Cong Wang
2017-02-01 21:16             ` Eric Dumazet
2017-02-01 21:22               ` Eric Dumazet
2017-02-01 23:29               ` Cong Wang
2017-02-01 23:48                 ` Eric Dumazet
2017-02-01 23:59                   ` Eric Dumazet
2017-02-02 18:01                     ` Cong Wang
2017-02-02 18:31                       ` [PATCH net] net: use a work queue to defer net_disable_timestamp() work Eric Dumazet
2017-02-03 21:18                         ` David Miller [this message]

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