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From: Roman Gushchin <klamm@yandex-team.ru>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>,
	paulmck@linux.vnet.ibm.com, 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>
Subject: Re: [PATCH v2] rcu: fix a race in hlist_nulls_for_each_entry_rcu macro
Date: Wed, 29 May 2013 13:17:52 +0400	[thread overview]
Message-ID: <51A5C7C0.5040304@yandex-team.ru> (raw)
In-Reply-To: <1369787693.3301.586.camel@edumazet-glaptop>

On 29.05.2013 04:34, Eric Dumazet wrote:
> On Tue, 2013-05-28 at 13:10 +0400, Roman Gushchin wrote:
>> On 28.05.2013 04:12, Eric Dumazet wrote:
>
>>> Adding a barrier() is probably what we want.
>>
>> I agree, inserting barrier() is also a correct and working fix.
>
> Yeah, but I can not find a clean way to put it inside the "for (;;)"

diff --git a/include/linux/rculist_nulls.h b/include/linux/rculist_nulls.h
index 2ae1371..74d5065 100644
--- a/include/linux/rculist_nulls.h
+++ b/include/linux/rculist_nulls.h
@@ -107,7 +107,7 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n,
   *
   */
  #define hlist_nulls_for_each_entry_rcu(tpos, pos, head, member)                        \
-       for (pos = rcu_dereference_raw(hlist_nulls_first_rcu(head));            \
+       for (({barrier();}), pos = rcu_dereference_raw(hlist_nulls_first_rcu(head)); \
                 (!is_a_nulls(pos)) &&                                           \
                 ({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1; }); \
                 pos = rcu_dereference_raw(hlist_nulls_next_rcu(pos)))




  parent reply	other threads:[~2013-05-29  9:18 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-21  9:05 [PATCH] rcu: fix a race in hlist_nulls_for_each_entry_rcu macro Roman Gushchin
2013-05-21 10:40 ` David Laight
2013-05-21 11:55   ` Roman Gushchin
2013-05-21 13:42     ` David Laight
2013-05-21 12:09 ` Paul E. McKenney
2013-05-21 12:46   ` Roman Gushchin
2013-05-21 12:58     ` Paul E. McKenney
2013-05-21 13:37   ` Eric Dumazet
2013-05-21 13:44   ` Eric Dumazet
2013-05-21 14:47     ` Roman Gushchin
2013-05-21 15:16       ` Eric Dumazet
2013-05-21 15:51         ` Roman Gushchin
2013-05-21 15:38       ` Eric Dumazet
2013-05-21 15:51         ` Roman Gushchin
2013-05-21 18:12         ` [PATCH v2] " Roman Gushchin
2013-05-22  2:01           ` Eric Dumazet
2013-05-22  5:49             ` Eric Dumazet
2013-05-22 11:58               ` Roman Gushchin
2013-05-22 12:30                 ` Eric Dumazet
2013-05-22 13:07                   ` Roman Gushchin
2013-05-22 17:45                     ` Paul E. McKenney
2013-05-22 19:17                       ` Roman Gushchin
2013-05-25 11:37                         ` Paul E. McKenney
2013-05-27 11:34                           ` Roman Gushchin
2013-05-27 17:55                           ` Roman Gushchin
2013-05-28  0:12                             ` Eric Dumazet
2013-05-28  9:10                               ` Roman Gushchin
2013-05-29  0:34                                 ` Eric Dumazet
2013-05-29  1:31                                   ` Paul E. McKenney
2013-05-29  5:08                                     ` Eric Dumazet
2013-05-29 10:09                                       ` Roman Gushchin
2013-05-29 19:06                                         ` Eric Dumazet
2013-05-30  8:25                                           ` Roman Gushchin
2013-06-02 23:31                                             ` Eric Dumazet
2013-06-03  2:58                                               ` David Miller
2013-06-03  3:12                                                 ` Eric Dumazet
2013-06-03  3:27                                                   ` David Miller
2013-06-03  3:42                                                     ` Paul E. McKenney
2013-06-03  3:47                                                       ` Eric Dumazet
2013-06-03  3:49                                                       ` David Miller
2013-06-03  6:05                                                         ` Paul E. McKenney
2013-06-10 18:29                                                         ` Boris B. Zhmurov
2013-06-10 18:51                                                           ` Eric Dumazet
2013-06-03  3:48                                                   ` Paul E. McKenney
2013-06-03  3:42                                                 ` Paul E. McKenney
2013-05-29  9:17                                   ` Roman Gushchin [this message]
2013-05-29  1:19                                 ` Paul E. McKenney
2013-05-22 13:27                   ` David Laight
2013-05-22 13:27                     ` David Laight
2013-05-22 13:36                     ` Eric Dumazet
2013-05-22 14:23                       ` David Laight
2013-05-22 14:23                         ` David Laight
2013-05-22 13:55                     ` Roman Gushchin
2013-05-22  9:58             ` Paul E. McKenney
2013-05-22 12:28               ` Eric Dumazet
2013-05-22 13:00                 ` Paul E. McKenney
2013-05-22 14:16                   ` Eric Dumazet

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