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Subject: Re: [PATCH 03/11] jump label: Base patch for jump label
From: Steven Rostedt <rostedt@goodmis.org>
To: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>,
        linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
        Andrew Morton <akpm@linux-foundation.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Andi Kleen <andi@firstfloor.org>, David Miller <davem@davemloft.net>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Rusty Russell <rusty@rustcorp.com.au>
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References: <20100923034910.867858597@goodmis.org>
	 <20100923035608.228041459@goodmis.org> <20100923143758.GA4022@Krystal>
	 <20100923153902.GD2825@redhat.com>
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Date: Thu, 23 Sep 2010 12:52:11 -0400
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On Thu, 2010-09-23 at 11:39 -0400, Jason Baron wrote:
> On Thu, Sep 23, 2010 at 10:37:58AM -0400, Mathieu Desnoyers wrote:

> I was thinking about the rcu_read_lock/synchronize_rcu() for this race.
> We can hold the rcu_read_lock() across the is_module_text_address()
> check in the jump label code, and then we can do in module.c:
> 
> mod->module_init = NULL;
> synchronize_rcu();
> module_free(mod, mod->module_init);

Um, isn't that last call the same as:

	module_free(mod, NULL); ?

I'll spend some time looking at this too.

-- Steve

> .
> .
> .
> 
> or we could push the rcu_read_lock() further down into
> is_module_address()?
> 
> thanks,
> 
> -Jason
>