Re: [RFC] [PATCH] Refuse kprobe insertion on add/sub_preempt_counter()

[Ananth N Mavinakayanahalli <ananth@in.ibm.com>]

On Wed, Feb 20, 2008 at 03:45:17PM +0530, Srinivasa Ds wrote:
> Kprobes makes use of preempt_disable(),preempt_enable_noresched() and these
> functions inturn call add/sub_preempt_count(). So we need to refuse user from 
> inserting probe in to these functions. 
> 
> This patch disallows user from probing add/sub_preempt_count(). 
> 
> Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com>

Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>

> ---
>  kernel/sched.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> Index: linux-2.6.25-rc2/kernel/sched.c
> ===================================================================
> --- linux-2.6.25-rc2.orig/kernel/sched.c
> +++ linux-2.6.25-rc2/kernel/sched.c
> @@ -3766,7 +3766,7 @@ void scheduler_tick(void)
> 
>  #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
> 
> -void add_preempt_count(int val)
> +void __kprobes add_preempt_count(int val)
>  {
>  	/*
>  	 * Underflow?
> @@ -3782,7 +3782,7 @@ void add_preempt_count(int val)
>  }
>  EXPORT_SYMBOL(add_preempt_count);
> 
> -void sub_preempt_count(int val)
> +void __kprobes sub_preempt_count(int val)
>  {
>  	/*
>  	 * Underflow?
> 
> 
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