Date: Fri, 18 Dec 2009 17:02:35 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: "Pan, Jacob jun" <jacob.jun.pan@intel.com>
cc: "H. Peter Anvin" <hpa@linux.intel.com>, "x86@kernel.org" <x86@kernel.org>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] x86: initialize stack canary in secondary start
In-Reply-To: <43F901BD926A4E43B106BF17856F07559A257B5F@orsmsx508.amr.corp.intel.com>
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References: <43F901BD926A4E43B106BF17856F07559A257B5F@orsmsx508.amr.corp.intel.com>
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On Thu, 17 Dec 2009, Pan, Jacob jun wrote:
> >From 06503838368350268a46528e134c1dad9f4f8c93 Mon Sep 17 00:00:00 2001
> From: Jacob Pan <jacob.jun.pan@intel.com>
> Date: Thu, 17 Sep 2009 07:36:43 -0700
> Subject: [PATCH 1/2] x86: initialize stack canary in secondary start
> 
> some secondary clockevent setup code needs to call request_irq, which will
> cause fake stack check failure in schedule() if voluntary preemption
> model is chosen, it is safe to have stack canary initialized here early,
> since start_secondary() does not return.

Where is it initialized now ? Shouldnt the current init be removed ?

Thanks,

	tglx

> Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com>
> ---
>  arch/x86/kernel/smpboot.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index 678d0b8..56ce974 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -48,6 +48,7 @@
>  #include <linux/err.h>
>  #include <linux/nmi.h>
>  #include <linux/tboot.h>
> +#include <linux/stackprotector.h>
>  
>  #include <asm/acpi.h>
>  #include <asm/desc.h>
> @@ -324,6 +325,9 @@ notrace static void __cpuinit start_secondary(void *unused)
>  	/* enable local interrupts */
>  	local_irq_enable();
>  
> +	/* to prevent fake stack check failure in clock setup */
> +	boot_init_stack_canary();
> +
>  	x86_cpuinit.setup_percpu_clockev();
>  
>  	wmb();
> -- 
> 1.6.5.3
> 
> 
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