Re: [PATCH 1/2] x86: initialize stack canary in secondary start

From: Thomas Gleixner
Date: Fri Dec 18 2009 - 11:03:35 EST


On Thu, 17 Dec 2009, Pan, Jacob jun wrote:
> >From 06503838368350268a46528e134c1dad9f4f8c93 Mon Sep 17 00:00:00 2001
> From: Jacob Pan <jacob.jun.pan@xxxxxxxxx>
> 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@xxxxxxxxx>
> ---
> 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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