From: Arjan van de Ven <arjan@infradead.org>
To: Andrea Arcangeli <andrea@qumranet.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Dave Jones <davej@redhat.com>, Roland Dreier <rdreier@cisco.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
David Miller <davem@davemloft.net>,
jeremy@goop.org, hugh@veritas.com, mingo@elte.hu,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] workaround minor lockdep bug triggered by mm_take_all_locks
Date: Mon, 4 Aug 2008 14:27:52 -0700 [thread overview]
Message-ID: <20080804142752.23a59073@infradead.org> (raw)
In-Reply-To: <20080804210954.GC12464@duo.random>
On Mon, 4 Aug 2008 23:09:54 +0200
Andrea Arcangeli <andrea@qumranet.com> wrote:
> On Mon, Aug 04, 2008 at 10:37:22PM +0200, Peter Zijlstra wrote:
> > You're so wrong it not even funny. It reports about deadlocks before
> > they happen. All it needs is to observe a lock order violation and
> > it
>
> Now tell me how it helps to report them... It tells me the system has
> crashed and where,
I think you totally misunderstand things then.
Lockdep will report a problem if it *ever* sees a BA order after it has
seen a BA order. They don't have to happen at the same time. Or even
within hours of eachother.
They MIGHT happen... in a narrow time window, when you have a deadlock.
But lockdep will warn you about the order violation without actually
having to dealock... because the AB is likely to be done already most
of the time when the BA happens.
next prev parent reply other threads:[~2008-08-04 21:29 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 [this message]
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
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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