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Subject: Re: [RFC] [PATCH 1/7] User Space Breakpoint Assistance Layer (UBP)
From: Peter Zijlstra <peterz@infradead.org>
To: Avi Kivity <avi@redhat.com>
Cc: ananth@in.ibm.com, Jim Keniston <jkenisto@us.ibm.com>,
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Date: Sun, 17 Jan 2010 16:03:13 +0100
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On Sun, 2010-01-17 at 16:59 +0200, Avi Kivity wrote:
> On 01/17/2010 04:52 PM, Peter Zijlstra wrote:
> > On Sun, 2010-01-17 at 16:39 +0200, Avi Kivity wrote:
> >    
> >> On 01/15/2010 11:50 AM, Peter Zijlstra wrote:
> >>      
> >>> As previously stated, I think poking at a process's address space is an
> >>> utter no-go.
> >>>
> >>>        
> >> Why not reserve an address space range for this, somewhere near the top
> >> of memory?  It doesn't have to be populated if it isn't used.
> >>      
> > Because I think poking at a process's address space like that is gross.
> > Also, if its fixed size you're imposing artificial limits on the number
> > of possible probes.
> >    
> 
> btw, an alternative is to require the caller to provide the address 
> space for this.  If the caller is in another process, we need to allow 
> it to play with the target's address space (i.e. mmap_process()).  I 
> don't think uprobes justifies this by itself, but mmap_process() can be 
> very useful for sandboxing with seccomp.

mmap_process() sounds utterly gross, one process playing with another
process's address space.. yuck!