From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH v2] rcu: fix a race in hlist_nulls_for_each_entry_rcu
 macro
Date: Wed, 22 May 2013 05:28:47 -0700
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Cc: Roman Gushchin <klamm@yandex-team.ru>,
	Dipankar Sarma <dipankar@in.ibm.com>, zhmurov@yandex-team.ru,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	"David S. Miller" <davem@davemloft.net>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	James Morris <jmorris@namei.org>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Patrick McHardy <kaber@trash.net>
To: paulmck@linux.vnet.ibm.com
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On Wed, 2013-05-22 at 02:58 -0700, Paul E. McKenney wrote:

> Now that I am more awake...
> 
> The RCU list macros assume that the list header is either statically
> allocated (in which case no ACCESS_ONCE() or whatever is needed) or
> that the caller did whatever was necessary to protect the list header,
> whether that be holding the right lock, using rcu_dereference() when
> traversing the pointer to the list header, or whatever.

Not sure what you mean, we do hold rcu_read_lock() here.

But when we jump back to begin, we do not do
"rcu_read_unlock()/rcu_read_lock()" pair.