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Subject: Re: [PATCH] kernel/time: Make /proc/timer_list mode 0400
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Marcus Meissner <meissner@suse.de>
Cc: tglx@linutronix.de, mingo@elte.hu, akpm@linux-foundation.org,
        rusty@rustcorp.com.au, torvalds@linux-foundation.org,
        linux-kernel@vger.kernel.org
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Date: Wed, 17 Nov 2010 18:33:51 +0100
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On Wed, 2010-11-17 at 18:21 +0100, Marcus Meissner wrote:
> On Wed, Nov 17, 2010 at 06:18:32PM +0100, Peter Zijlstra wrote:
> > On Wed, 2010-11-17 at 18:08 +0100, Marcus Meissner wrote:
> > > Hi,
> > > 
> > > /proc/timer_list contains kernel addresses, like e.g.:
> > >  #0: <c000000001404158>, tick_sched_timer, S:01, .tick_nohz_restart_sched_tick, swapper/0
> > >  ...
> > > 
> > > Avoid leaking them to user space to make writing kernel exploits a bit harder.
> > > 
> > > (I currently cannot think of a userland tool that uses this, this is
> > > likely pretty much root-only.)
> > 
> > iirc powertop parses this..
> 
> powertop already says on startup:
> 
> 	PowerTOP needs to be run as root to collect enough information

I know, but you said you didn't know of a tool that used the file.. now
you do ;-)
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