From: Borislav Petkov <bp@alien8.de>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Yong Zhang <yong.zhang0@gmail.com>,
linux-kernel@vger.kernel.org, sergey.senozhatsky@gmail.com,
bp@alien8.de, Ingo Molnar <mingo@elte.hu>,
Tejun Heo <tj@kernel.org>, David Rientjes <rientjes@google.com>
Subject: Re: [PATCH 1/4] lockdep: lock_set_subclass() fix
Date: Mon, 7 Nov 2011 14:54:53 +0100 [thread overview]
Message-ID: <20111107135452.GA2975@gere.osrc.amd.com> (raw)
In-Reply-To: <1320669279.18053.29.camel@twins>
On Mon, Nov 07, 2011 at 01:34:39PM +0100, Peter Zijlstra wrote:
> On Fri, 2011-11-04 at 17:26 +0800, Yong Zhang wrote:
> > Since commit f59de89 [lockdep: Clear whole lockdep_map on initialization],
> > lockdep_init_map() will clear all the struct. But it will break
> > lock_set_class()/lock_set_subclass(). A typical race condition
> > is like below:
>
> This is a horridly ugly patch, why not simply revert that memset commit?
> I really can't see the point of that, and keeping the name/key pointers
> around (which can only be over-written with the same values, right?)
> would also cure the problem.
FWIW,
I ran the box with the memset commit reverted for a couple of days
before applying Young's patches and it didn't show any signs of
problems.
--
Regards/Gruss,
Boris.
next prev parent reply other threads:[~2011-11-07 13:54 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-04 9:26 [PATCH 0/4] patches to cure race in lock_set_class() Yong Zhang
2011-11-04 9:26 ` [PATCH 1/4] lockdep: lock_set_subclass() fix Yong Zhang
2011-11-07 12:34 ` Peter Zijlstra
2011-11-07 13:31 ` Yong Zhang
2011-11-07 14:03 ` Tejun Heo
2011-11-07 13:54 ` Borislav Petkov [this message]
2011-11-07 15:28 ` Vegard Nossum
2011-11-07 16:10 ` Peter Zijlstra
2011-11-07 16:21 ` Tejun Heo
2011-11-07 16:26 ` Peter Zijlstra
2011-11-08 2:58 ` Yong Zhang
2011-11-08 3:02 ` Yong Zhang
2011-11-08 7:56 ` Peter Zijlstra
2011-11-08 8:14 ` Yong Zhang
2011-11-08 8:46 ` Peter Zijlstra
2011-11-08 9:07 ` Yong Zhang
2011-11-08 9:37 ` Yong Zhang
2011-11-08 9:40 ` Peter Zijlstra
2011-11-09 8:04 ` [PATCH 1/2] lockdep: kmemcheck: annotate ->lock in lockdep_init_map() Yong Zhang
2011-11-09 8:07 ` [PATCH 2/2] lockdep: always try to set ->class_cache in register_lock_class() lockdep_init_map() Yong Zhang
2011-11-18 23:39 ` [tip:core/locking] lockdep: Always " tip-bot for Yong Zhang
2011-12-06 9:39 ` [tip:core/locking] lockdep, kmemcheck: Annotate ->lock in lockdep_init_map() tip-bot for Yong Zhang
2011-12-06 19:56 ` David Rientjes
2011-12-06 20:14 ` [tip:perf/urgent] " tip-bot for Yong Zhang
2011-11-08 2:22 ` [PATCH 1/4] lockdep: lock_set_subclass() fix Yong Zhang
2011-11-04 9:26 ` [RFC PATCH 2/4] lockdep: Let register_lock_class() can be called with/without graph_lock Yong Zhang
2011-11-04 9:26 ` [RFC PATCH 3/4] lockdep: split lockdep_init_map() Yong Zhang
2011-11-04 9:26 ` [RFC PATCH 4/4] lockdep: fix race condition in __lock_set_class() Yong Zhang
2011-11-07 12:30 ` Peter Zijlstra
2011-11-07 13:26 ` Yong Zhang
2011-11-06 11:52 ` [PATCH 0/4] patches to cure race in lock_set_class() Borislav Petkov
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