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Subject: Re: [RFC][PATCH 07/11] perf: Provide PERF_SAMPLE_REGS
From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: mingo@elte.hu, linux-kernel@vger.kernel.org, paulus@samba.org,
       eranian@google.com, robert.richter@amd.com
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Date: Thu, 04 Mar 2010 09:58:07 +0100
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On Wed, 2010-03-03 at 23:02 +0100, Frederic Weisbecker wrote:
> On Wed, Mar 03, 2010 at 05:39:43PM +0100, Peter Zijlstra wrote:
> > Simply copy out the provided pt_regs in a u64 aligned fashion.
> > 
> > XXX: do task_pt_regs() and get_irq_regs() always clear everything or
> >      are we now leaking data?
> 
> 
> It looks like there is a leak in case of non trace syscalls.
> where we don't appear to save r12-15.
> 
> Then task_pt_regs() may leak the top of a process stack...?


Right, I was afraid of that. I've put this PERF_SAMPLE_REGS thing in the
freezer for now as people seem unsure how to deal with it.