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From: Suresh Siddha <suresh.b.siddha@intel.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: "Jan.Grossmann@kielnet.net" <Jan.Grossmann@kielnet.net>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"jbarnes@virtuousgeek.org" <jbarnes@virtuousgeek.org>,
	"Woodhouse, David" <david.woodhouse@intel.com>,
	"Han, Weidong" <weidong.han@intel.com>,
	"Song, Youquan" <youquan.song@intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"stable@kernel.org" <stable@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: BUG: null pointer deref in dmar_ir_support
Date: Fri, 02 Apr 2010 11:28:33 -0700	[thread overview]
Message-ID: <1270232913.2870.60.camel@sbs-t61.sc.intel.com> (raw)
In-Reply-To: <20100402182034.GA27304@elte.hu>

On Fri, 2010-04-02 at 11:20 -0700, Ingo Molnar wrote:
> * Suresh Siddha <suresh.b.siddha@intel.com> wrote:
> 
> > @@ -1640,8 +1640,10 @@ int __init APIC_init_uniprocessor(void)
> >  	}
> >  #endif
> >  
> > +#ifndef CONFIG_SMP
> >  	enable_IR_x2apic();
> >  	default_setup_apic_routing();
> > +#endif
> 
> Instead of adding yet another ugly #ifdef please hide these details properly, 
> by making enable_IR_x2apic() and default_setup_apic_routing() a NOP on !SMP.

Ingo, These are not nops on !SMP. We should call these functions from
APIC_init_uniprocessor() only if it is a UP kernel. For SMP kernel they
are called from some where else.

With the current code, on SMP and with non SMP motherboard we were
calling these routines twice which cause problem.

I wanted to keep the patch simple for urgent/backport. I will clean this
by restructuring the init code for 2.6.35

thanks,
suresh


  reply	other threads:[~2010-04-02 18:29 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <4BAD1676.9090704@kielnet.net>
     [not found] ` <1270057394.2866.9.camel@sbs-t61.sc.intel.com>
     [not found]   ` <4BB395B0.6090007@kielnet.net>
2010-04-01  1:04     ` Suresh Siddha
2010-04-01 18:20       ` Jan.Grossmann
2010-04-01 20:04         ` Suresh Siddha
2010-04-02 17:21           ` Suresh Siddha
2010-04-02 18:20       ` Ingo Molnar
2010-04-02 18:28         ` Suresh Siddha [this message]
2010-04-02 18:45           ` Ingo Molnar
2010-04-02 19:14       ` [tip:x86/urgent] x86: Fix double enable_IR_x2apic() call on SMP kernel on !SMP boards tip-bot for Suresh Siddha

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