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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Jay Vosburgh <jay.vosburgh@canonical.com>
Cc: Yanko Kaneti <yaneti@declera.com>,
	Josh Boyer <jwboyer@fedoraproject.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Cong Wang <cwang@twopensource.com>, Kevin Fenzi <kevin@scrye.com>,
	netdev <netdev@vger.kernel.org>,
	"Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>,
	mroos@linux.ee, tj@kernel.org
Subject: Re: localed stuck in recent 3.18 git in copy_net_ns?
Date: Fri, 24 Oct 2014 19:03:24 -0700	[thread overview]
Message-ID: <20141025020324.GA28247@linux.vnet.ibm.com> (raw)
In-Reply-To: <10136.1414196448@famine>

On Fri, Oct 24, 2014 at 05:20:48PM -0700, Jay Vosburgh wrote:
> Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> 
> >On Fri, Oct 24, 2014 at 03:59:31PM -0700, Paul E. McKenney wrote:
> [...]
> >> Hmmm...  It sure looks like we have some callbacks stuck here.  I clearly
> >> need to take a hard look at the sleep/wakeup code.
> >> 
> >> Thank you for running this!!!
> >
> >Could you please try the following patch?  If no joy, could you please
> >add rcu:rcu_nocb_wake to the list of ftrace events?
> 
> 	I tried the patch, it did not change the behavior.
> 
> 	I enabled the rcu:rcu_barrier and rcu:rcu_nocb_wake tracepoints
> and ran it again (with this patch and the first patch from earlier
> today); the trace output is a bit on the large side so I put it and the
> dmesg log at:
> 
> http://people.canonical.com/~jvosburgh/nocb-wake-dmesg.txt
> 
> http://people.canonical.com/~jvosburgh/nocb-wake-trace.txt

Thank you again!

Very strange part of the trace.  The only sign of CPU 2 and 3 are:

    ovs-vswitchd-902   [000] ....   109.896840: rcu_barrier: rcu_sched Begin cpu -1 remaining 0 # 0
    ovs-vswitchd-902   [000] ....   109.896840: rcu_barrier: rcu_sched Check cpu -1 remaining 0 # 0
    ovs-vswitchd-902   [000] ....   109.896841: rcu_barrier: rcu_sched Inc1 cpu -1 remaining 0 # 1
    ovs-vswitchd-902   [000] ....   109.896841: rcu_barrier: rcu_sched OnlineNoCB cpu 0 remaining 1 # 1
    ovs-vswitchd-902   [000] d...   109.896841: rcu_nocb_wake: rcu_sched 0 WakeNot
    ovs-vswitchd-902   [000] ....   109.896841: rcu_barrier: rcu_sched OnlineNoCB cpu 1 remaining 2 # 1
    ovs-vswitchd-902   [000] d...   109.896841: rcu_nocb_wake: rcu_sched 1 WakeNot
    ovs-vswitchd-902   [000] ....   109.896842: rcu_barrier: rcu_sched OnlineNoCB cpu 2 remaining 3 # 1
    ovs-vswitchd-902   [000] d...   109.896842: rcu_nocb_wake: rcu_sched 2 WakeNotPoll
    ovs-vswitchd-902   [000] ....   109.896842: rcu_barrier: rcu_sched OnlineNoCB cpu 3 remaining 4 # 1
    ovs-vswitchd-902   [000] d...   109.896842: rcu_nocb_wake: rcu_sched 3 WakeNotPoll
    ovs-vswitchd-902   [000] ....   109.896843: rcu_barrier: rcu_sched Inc2 cpu -1 remaining 4 # 2

The pair of WakeNotPoll trace entries says that at that point, RCU believed
that the CPU 2's and CPU 3's rcuo kthreads did not exist.  :-/

More diagnostics in order...

							Thanx, Paul


  reply	other threads:[~2014-10-25  2:07 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-20 20:15 localed stuck in recent 3.18 git in copy_net_ns? Kevin Fenzi
2014-10-20 20:43 ` Dave Jones
2014-10-20 20:53   ` Kevin Fenzi
2014-10-21 21:12     ` Kevin Fenzi
2014-10-22 17:12       ` Josh Boyer
2014-10-22 17:37         ` Cong Wang
2014-10-22 17:49           ` Josh Boyer
2014-10-22 17:53           ` Eric W. Biederman
2014-10-22 18:11             ` Paul E. McKenney
2014-10-22 18:25               ` Eric W. Biederman
2014-10-22 18:55                 ` Paul E. McKenney
2014-10-22 19:33                   ` Josh Boyer
2014-10-22 22:40                     ` Yanko Kaneti
2014-10-22 23:24                       ` Paul E. McKenney
2014-10-23  6:09                         ` Yanko Kaneti
2014-10-23 12:27                           ` Paul E. McKenney
2014-10-23 15:33                             ` Paul E. McKenney
     [not found]                               ` <CA+5PVA4H6EAf6cBc4a_8W8x4Mgppjc5GsskKaCRry2jq+LP+FA@mail.gmail.com>
2014-10-23 16:28                                 ` Paul E. McKenney
2014-10-23 19:51                               ` Yanko Kaneti
2014-10-23 20:05                                 ` Paul E. McKenney
2014-10-23 21:45                                   ` Yanko Kaneti
2014-10-23 22:04                                     ` Paul E. McKenney
2014-10-24  4:48                                       ` Jay Vosburgh
2014-10-24 14:50                                         ` Paul E. McKenney
2014-10-24 18:20                                           ` Jay Vosburgh
2014-10-24 18:33                                             ` Paul E. McKenney
2014-10-24  9:08                                       ` Yanko Kaneti
2014-10-24 15:40                                         ` Paul E. McKenney
2014-10-24 16:29                                           ` Yanko Kaneti
2014-10-24 16:54                                             ` Paul E. McKenney
2014-10-24 17:09                                               ` Yanko Kaneti
2014-10-24 17:20                                                 ` Paul E. McKenney
2014-10-24 17:35                                                   ` Yanko Kaneti
2014-10-24 18:32                                                     ` Paul E. McKenney
2014-10-24 18:49                                                       ` Jay Vosburgh
2014-10-24 18:57                                                         ` Paul E. McKenney
2014-10-24 20:15                                                           ` Paul E. McKenney
2014-10-24 21:25                                                       ` Yanko Kaneti
2014-10-24 21:49                                                         ` Paul E. McKenney
2014-10-24 22:02                                                           ` Jay Vosburgh
2014-10-24 22:16                                                             ` Paul E. McKenney
2014-10-24 22:41                                                               ` Jay Vosburgh
2014-10-24 22:34                                                           ` Jay Vosburgh
2014-10-24 22:59                                                             ` Paul E. McKenney
2014-10-24 23:05                                                               ` Paul E. McKenney
2014-10-25  0:20                                                                 ` Jay Vosburgh
2014-10-25  2:03                                                                   ` Paul E. McKenney [this message]
2014-10-25  4:33                                                                     ` Jay Vosburgh
2014-10-25  5:16                                                                       ` Paul E. McKenney
2014-10-25 16:38                                                                         ` Jay Vosburgh
2014-10-25 18:18                                                                           ` Paul E. McKenney
2014-10-27 17:45                                                                             ` Paul E. McKenney
2014-10-27 20:43                                                                               ` Jay Vosburgh
2014-10-27 21:07                                                                                 ` Paul E. McKenney
2014-10-28  8:12                                                                               ` Yanko Kaneti
2014-10-28 12:50                                                                                 ` Paul E. McKenney
2014-10-28 13:00                                                                                   ` Yanko Kaneti
2014-10-28 15:54                                                                                     ` Kevin Fenzi
2014-10-28 16:15                                                                                       ` Paul E. McKenney
2014-10-25 12:09                                                           ` Yanko Kaneti
2014-10-25 13:38                                                             ` Paul E. McKenney
2014-10-22 17:59           ` Paul E. McKenney
2014-10-22 18:03             ` Josh Boyer

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