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Date: Tue, 30 Mar 2010 09:45:55 -0400
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, Randy Dunlap <randy.dunlap@oracle.com>,
       Eric Dumazet <dada1@cosmosbay.com>,
       Rusty Russell <rusty@rustcorp.com.au>, Tejun Heo <tj@kernel.org>,
       Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@linux-foundation.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Greg Kroah-Hartman <gregkh@suse.de>,
       Steven Rostedt <rostedt@goodmis.org>, stable <stable@kernel.org>
Subject: Re: [PATCH] lockdep fix incorrect percpu usage
Message-ID: <20100330134555.GA20673@Krystal>
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* Peter Zijlstra (peterz@infradead.org) wrote:
> On Mon, 2010-03-29 at 23:34 -0400, Mathieu Desnoyers wrote:
> > Should use per_cpu_ptr() to obfuscate the per cpu pointers (RELOC_HIDE is needed
> > for per cpu pointers).
> > 
> > git blame points to commit:
> > 
> > lockdep.c: commit 8e18257d29238311e82085152741f0c3aa18b74d
> > 
> > But it's really just moving the code around. But it's enough to say that the
> > problems appeared before Jul 19 01:48:54 2007, which brings us back to 2.6.23.
> > 
> > So it should be applied to stable 2.6.23.x to 2.6.33.x (or whichever of these
> > stable branches are still maintained) and to mainline 2.6.34-rc2.
> 
> well, definately not to mainline, since that code is utterly busted in
> mainline due to recent per-cpu changes.

How recent ? I'm based on 

commit f57d4e859a8acd63f878cd0534ec4b990b1710dc
Merge: 0528faa... eed6351...
Author: Ingo Molnar <mingo@elte.hu>
Date:   Mon Mar 29 18:56:00 2010 +0200

from -tip and I see the problem there, both in module.c and lockdep.c.

Thanks,

Mathieu


-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com