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From: Jarek Poplawski <jarkao2@gmail.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Denys Fedoryschenko <denys@visp.net.lb>,
	Chris Caputo <ccaputo@alt.net>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	Badalian Vyacheslav <slavon@bigtelecom.ru>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: deadlocks if use htb
Date: Thu, 15 Jan 2009 09:01:20 +0000	[thread overview]
Message-ID: <20090115090120.GE4190@ff.dom.local> (raw)
In-Reply-To: <1231943283.14825.14.camel@laptop>

On Wed, Jan 14, 2009 at 03:28:03PM +0100, Peter Zijlstra wrote:
...
> Right, found all that...
> 
> Can't spot anything obviously wrong though.. hrtimer_start*() does
> remove_hrtimer() which checks STATE_ENQUEUED, STATE_PENDING and pulls it
> off the relevant list before it continues the enqueue.
> 
> However a loop in enqueue_hrtimer() would suggest a corrupted RB-tree,
> but I cannot find an RB-op that doesn't hold base-lock.
> 

I've revisited it yesterday, and if I don't miss something, there is
possible a scenario similar to this:

cpu1:				cpu2:

run_hrtimer_pending
spin_unlock
restart = fn(timer)

				hrtimer_start
				enqueue_hrtimer

				hrtimer_start
				remove_hrtimer
				(the HRTIMER_STATE_CALLBACK is removed)

				switch_hrtimer_base
spin_lock
(not this hrtimer's anymore)
__remove_hrtimer
list_add_tail			enqueue_hrtimer


Jarek P.

  parent reply	other threads:[~2009-01-15  9:02 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20081010075640.GA5204@ff.dom.local>
     [not found] ` <48EF17EA.5020306@bigtelecom.ru>
     [not found]   ` <20081010090426.GA6054@ff.dom.local>
     [not found]     ` <20081010095129.GB6054@ff.dom.local>
     [not found]       ` <48F6FB3E.7060903@bigtelecom.ru>
     [not found]         ` <20081016084027.GA17632@ff.dom.local>
     [not found]           ` <48FEC302.5090707@bigtelecom.ru>
2008-10-22  7:02             ` deadlocks if use htb Jarek Poplawski
2008-12-10 15:14               ` Badalian Vyacheslav
2008-12-11  8:46                 ` Jarek Poplawski
2008-12-15 11:13                   ` Jarek Poplawski
2008-12-16  7:37                     ` Badalian Vyacheslav
2008-12-18  6:43                     ` Badalian Vyacheslav
2008-12-18  8:17                       ` Jarek Poplawski
2008-12-18 11:23                         ` Badalian Vyacheslav
2008-12-18 11:37                           ` Jarek Poplawski
2009-01-14  2:43                         ` Chris Caputo
2009-01-14  6:39                           ` Jarek Poplawski
2009-01-14 12:17                             ` Denys Fedoryschenko
2009-01-14 12:36                               ` Jarek Poplawski
2009-01-14 12:41                                 ` Denys Fedoryschenko
2009-01-14 12:50                               ` Peter Zijlstra
2009-01-14 13:04                                 ` Jarek Poplawski
2009-01-14 13:05                                 ` Denys Fedoryschenko
2009-01-14 13:12                                   ` Jarek Poplawski
2009-01-14 13:15                                     ` Peter Zijlstra
2009-01-14 13:19                                       ` Denys Fedoryschenko
2009-01-14 13:26                                       ` Jarek Poplawski
2009-01-14 13:32                                         ` Peter Zijlstra
2009-01-14 13:57                                           ` Jarek Poplawski
2009-01-14 14:13                                           ` Jarek Poplawski
2009-01-14 14:28                                             ` Peter Zijlstra
2009-01-14 14:39                                               ` Jarek Poplawski
2009-01-15  9:01                                               ` Jarek Poplawski [this message]
2009-01-15 10:46                                                 ` Peter Zijlstra
2009-01-15 10:54                                                   ` Jarek Poplawski
2009-01-14 18:02                                 ` Chris Caputo
2009-01-15  6:53                                   ` Jarek Poplawski
2009-01-15  7:12                                     ` Badalian Vyacheslav
2009-01-15  8:09                                       ` Jarek Poplawski
2009-01-15  9:01                                         ` Denys Fedoryschenko
2009-01-15  9:06                                           ` Jarek Poplawski
2009-01-15  9:40                                             ` Badalian Vyacheslav
2009-01-15  9:54                                               ` Jarek Poplawski
2009-01-15  9:57                                                 ` Denys Fedoryschenko
2009-01-15 10:06                                                   ` Jarek Poplawski
2009-01-15 10:10                                                   ` Jarek Poplawski
2009-01-15 10:40                                                     ` Denys Fedoryschenko
2009-01-15  7:26                                     ` Chris Caputo
2009-01-15  7:54                                       ` Jarek Poplawski
2009-01-15  9:45                                         ` Jarek Poplawski
2009-01-15 12:00                                           ` Chris Caputo
2009-01-15 12:18                                             ` Jarek Poplawski
2009-01-15 13:53                                               ` Chris Caputo
2009-01-16  6:51                                                 ` Badalian Vyacheslav
2009-01-19  5:46                                     ` David Miller
2009-01-19  6:57                                       ` [PATCH] " Jarek Poplawski
2009-01-19  7:42                                         ` Badalian Vyacheslav
2009-01-19  7:57                                           ` Jarek Poplawski
2009-01-20  1:29                                             ` David Miller

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