linux-kernel - Re: 2.6.{26.2,27-rc} oops on virtualbox

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Date:	Tue, 26 Aug 2008 13:18:22 -0400
From:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
To:	"Luiz Fernando N. Capitulino" <lcapitulino@...driva.com.br>
Cc:	Gerhard Brauer <gerhard.brauer@....de>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>,
	linux-kernel@...r.kernel.org
Subject: Re: 2.6.{26.2,27-rc} oops on virtualbox

* Luiz Fernando N. Capitulino (lcapitulino@...driva.com.br) wrote:
> Em Tue, 26 Aug 2008 10:53:38 -0400
> Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca> escreveu:
> 
> | Then, after having tested (2), try this on top of it :
> | 
> | In arch/x86/kernel/alternative.c, alternatives_smp_switch()
> | 
> | Add   unsigned long flags;
> | Change 
> | spin_lock -> spin_lock_irqsave(&smp_alt, flags);
> | spin_unlock(&smp_alt); -> spin_unlock_irqrestore(&smp_alt, flags);
> 
>  Hmm, I can't find spin_lock functions in alternatives_smp_switch()
> looks like the current implementation is now using mutexes.
> 

Sorry, I was looking directly at the commit which caused the problem.
Yes, these modif should go on top of the text_poke -> text_poke_early.

So in current mainline, change, in alternatives_smp_switch() :

mutex_lock(&smp_alt);
...

mutex_unlock(&smp_alt);

to

mutex_lock(&smp_alt);
local_irq_save(flags);
...

local_irq_restore(flags);
mutex_unlock(&smp_alt);

Thanks,

Mathieu

>  What tree are you referring to?
> 
> -- 
> Luiz Fernando N. Capitulino

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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