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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	David Miller <davem@davemloft.net>,
	hugh@veritas.com, mingo@elte.hu, akpm@linux-foundation.org,
	linux-kernel@vger.kernel.org, davej@redhat.com
Subject: Re: [RFC][PATCH 7/7] lockdep: spin_lock_nest_lock()
Date: Mon, 04 Aug 2008 12:26:36 -0700	[thread overview]
Message-ID: <489757EC.3000309@goop.org> (raw)
In-Reply-To: <1217876046.3589.61.camel@twins>

Peter Zijlstra wrote:
>>    3. release the outer lock before releasing the inner locks
>>     
>
> Only if you then release the inner locks in the reverse order you took
> them - the nested release code (releasing a lock that is not on the top
> of the stack) basically pops and pushes all the locks, the push will
> fail if the outer lock is released.
>   

OK.  I don't actually need to do this, but I was asking for 
completeness.  But to clarify, you only need to do the reverse unlock if 
you do it after unlocking the outer lock?  If you're still holding the 
outer lock, you can unlock in any order?

>> but it's not OK to try to use different outer locks for a given inner lock.
>>     
>
> It doesn't validate this part - as with most lockdep annotations you can
> annotate away real deadlocks.
>   

Hm, OK.


    J

  reply	other threads:[~2008-08-04 19:27 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-04 13:03 [RFC][PATCH 0/7] lockdep Peter Zijlstra
2008-08-04 13:03 ` [RFC][PATCH 1/7] lockdep: Fix combinatorial explosion in lock subgraph traversal Peter Zijlstra
2008-08-05  8:34   ` David Miller
2008-08-05  8:46     ` Peter Zijlstra
2008-08-13  3:48       ` Tim Pepper
2008-08-13 10:56         ` Ingo Molnar
2008-08-04 13:03 ` [RFC][PATCH 2/7] lockdep: lock_set_subclass - reset a held locks subclass Peter Zijlstra
2008-08-05  8:35   ` David Miller
2008-08-04 13:03 ` [RFC][PATCH 3/7] lockdep: re-annotate scheduler runqueues Peter Zijlstra
2008-08-05  8:35   ` David Miller
2008-08-04 13:03 ` [RFC][PATCH 4/7] lockdep: shrink held_lock structure Peter Zijlstra
2008-08-05 16:08   ` Peter Zijlstra
2008-08-06  7:17   ` Peter Zijlstra
2008-08-04 13:03 ` [RFC][PATCH 5/7] lockdep: map_acquire Peter Zijlstra
2008-08-04 13:03 ` [RFC][PATCH 6/7] lockdep: lock protection locks Peter Zijlstra
2008-08-04 13:03 ` [RFC][PATCH 7/7] lockdep: spin_lock_nest_lock() Peter Zijlstra
2008-08-04 14:07   ` Roland Dreier
2008-08-04 14:19     ` Peter Zijlstra
2008-08-04 14:26       ` Roland Dreier
2008-08-04 14:32         ` Peter Zijlstra
2008-08-04 14:53           ` Dave Jones
2008-08-04 14:56             ` Peter Zijlstra
2008-08-04 16:26               ` Andrea Arcangeli
2008-08-04 16:38                 ` Peter Zijlstra
2008-08-04 17:27                   ` Andrea Arcangeli
2008-08-04 17:46                     ` Andrea Arcangeli
2008-08-04 17:57                       ` [PATCH] workaround minor lockdep bug triggered by mm_take_all_locks Andrea Arcangeli
2008-08-04 18:48                         ` Peter Zijlstra
2008-08-04 18:56                           ` Roland Dreier
2008-08-04 19:05                             ` Peter Zijlstra
2008-08-04 20:15                           ` Andrea Arcangeli
2008-08-04 20:37                             ` Peter Zijlstra
2008-08-04 21:09                               ` Andrea Arcangeli
2008-08-04 21:14                                 ` Pekka Enberg
2008-08-04 21:30                                   ` Andrea Arcangeli
2008-08-04 21:41                                     ` Andrew Morton
2008-08-04 22:12                                       ` Andrea Arcangeli
2008-08-04 21:42                                     ` Arjan van de Ven
2008-08-04 22:30                                       ` Andrea Arcangeli
2008-08-04 23:38                                         ` Arjan van de Ven
2008-08-05  0:47                                           ` Andrea Arcangeli
2008-08-04 21:27                                 ` Arjan van de Ven
2008-08-04 21:54                                   ` Andrea Arcangeli
2008-08-04 21:57                                 ` David Miller
2008-08-05  2:00                                 ` Roland Dreier
2008-08-05  2:18                                   ` Andrea Arcangeli
2008-08-05 12:02                                     ` Roland Dreier
2008-08-05 12:20                                       ` Andrea Arcangeli
2008-08-04 18:48                     ` [RFC][PATCH 7/7] lockdep: spin_lock_nest_lock() Peter Zijlstra
2008-08-04 21:32                   ` David Miller
2008-08-04 18:06   ` Jeremy Fitzhardinge
2008-08-04 18:54     ` Peter Zijlstra
2008-08-04 19:26       ` Jeremy Fitzhardinge [this message]
2008-08-04 19:31         ` Linus Torvalds
2008-08-04 19:39           ` Peter Zijlstra
2008-08-04 20:16           ` Jeremy Fitzhardinge
2008-10-08 15:27           ` Steven Rostedt
2008-10-08 15:43             ` Linus Torvalds
2008-10-08 16:03               ` Steven Rostedt
2008-10-08 16:19                 ` Linus Torvalds
2008-10-08 16:53                   ` Steven Rostedt
2008-10-08 15:52             ` Nick Piggin
2008-10-08 17:18               ` Steven Rostedt
2008-08-07 11:25   ` Peter Zijlstra
2008-08-07 11:25 ` [RFC][PATCH 8/7] lockdep: annotate mm_take_all_locks() Peter Zijlstra
2008-08-07 11:25 ` [RFC][PATCH 9/7] mm: fix mm_take_all_locks() locking order Peter Zijlstra
2008-08-07 12:14   ` Hugh Dickins
2008-08-07 12:41     ` Peter Zijlstra
2008-08-07 13:27       ` Hugh Dickins
2008-08-07 21:46   ` Andrea Arcangeli
2008-08-08  1:34     ` Andrea Arcangeli
2008-08-08  7:16     ` Peter Zijlstra
2008-08-11 10:08 ` [RFC][PATCH 0/7] lockdep Ingo Molnar

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