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From: Gao feng <gaofeng@cn.fujitsu.com>
To: Eric Dumazet <eric.dumazet@gmail.com>,
	Ding Tianhong <dingtianhong@huawei.com>
Cc: David Miller <davem@davemloft.net>,
	yoshfuji@linux-ipv6.org, joe@perches.com, vfalico@redhat.com,
	netdev@vger.kernel.org
Subject: Re: [PATCH net] net: neighbour: add neighbour dead check for neigh_timer_handler()
Date: Thu, 05 Dec 2013 08:32:00 +0800	[thread overview]
Message-ID: <529FC980.8020101@cn.fujitsu.com> (raw)
In-Reply-To: <1386170645.30495.108.camel@edumazet-glaptop2.roam.corp.google.com>

On 12/04/2013 11:24 PM, Eric Dumazet wrote:
> On Wed, 2013-12-04 at 17:16 +0800, Ding Tianhong wrote:
>>>> 						base->running_timer = neigh->timer;
>>>> 						neigh_timer_handler() => at this time, refcnt is 2;
>>>>
>>>> user->	neigh_changeaddr()
>>>> 	neigh_flush_dev();
>>>> 	neigh_del_imer, refcnt dec to 1;
>>>
>>> Nope : del_timer() would return 0 here, so we do not decrement refcnt.
>>>
>>
>> The first call for del_timer() will return 1, because the timer->entry.next is not NULL,
>> then in the neigh_destroy, the del_timer() again will return 0 because timer->entry.next is NULL. 
> 
> Again no. You are very mistaken.
> 
> del_timer() return code is not a hint. Its a precise meaning.
> 
> It cannot return 1 if the timer function is running or is about to run.
> 
> If you believe there is  bug in del_timer(), fix it ;)
> 
> 

Yes, you are right, __run_timers did this job.
So We still don't know what's the root reason.

  reply	other threads:[~2013-12-05  0:30 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-03 13:48 [PATCH net] net: neighbour: add neighbour dead check for neigh_timer_handler() Ding Tianhong
2013-12-03 15:03 ` Hannes Frederic Sowa
2013-12-04  1:36   ` Ding Tianhong
2013-12-03 16:28 ` Eric Dumazet
2013-12-04  1:59   ` Ding Tianhong
2013-12-03 16:37 ` David Miller
2013-12-04  2:37 ` Gao feng
2013-12-04  4:04   ` Ding Tianhong
2013-12-04  4:21     ` David Miller
2013-12-04  6:19       ` Ding Tianhong
2013-12-04  6:27         ` Eric Dumazet
2013-12-04  9:16           ` Ding Tianhong
2013-12-04 10:10             ` Gao feng
2013-12-04 15:24             ` Eric Dumazet
2013-12-05  0:32               ` Gao feng [this message]
2013-12-05  3:17                 ` Ding Tianhong
2013-12-18  6:37                   ` Ding Tianhong
2013-12-18  7:51                     ` Hannes Frederic Sowa
2013-12-18  8:19                       ` Ding Tianhong
2013-12-18  8:41                         ` Hannes Frederic Sowa
2013-12-18  8:57                           ` Ding Tianhong
2013-12-18  9:28                             ` Hannes Frederic Sowa
2013-12-18 10:02                               ` Ding Tianhong
2013-12-18 10:21                                 ` Hannes Frederic Sowa
2013-12-18 11:57                                   ` Ding Tianhong
2013-12-18 14:27                                     ` Hannes Frederic Sowa
2013-12-18 15:12                                       ` Ding Tianhong
2013-12-18 15:46                                         ` Hannes Frederic Sowa
2013-12-19  3:32                                           ` Ding Tianhong
2013-12-04  6:36         ` David Miller

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