Re: [PATCH 19/21] i386 Kprobes semaphore fix

[Zachary Amsden]

Ingo Molnar wrote:

> * Zachary Amsden <zach@xxxxxxxxxx> wrote:
>
>  
>
> > > I believe user space kprobes are being worked on by some IBM India folks 
> > > yes.
> > >      
> > I'm convinced this is pointless.  What does it buy you over a ptrace 
> > based debugger?  Why would you want extra code running in the kernel 
> > that can be done perfectly well in userspace?
> >    
>
> kprobes are not just for 'debuggers', they are also used for tracing and 
> other dynamic instrumentation in projects like systemtap. Ptrace is way 
> too slow and limited for things like that.
>  

Well, if there is a justification for it, that means we really should 
handle all the nasty EIP conversion cases due to segmentation and v8086 
mode in the kprobes code.  I was hoping that might not be the case.

Zach
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