Re: [RFC] [PATCH 4/7] Uprobes Implementation

From: Peter Zijlstra
Date: Fri Jan 15 2010 - 08:17:15 EST


On Fri, 2010-01-15 at 18:38 +0530, Srikar Dronamraju wrote:
> * Peter Zijlstra <peterz@xxxxxxxxxxxxx> [2010-01-15 11:33:27]:
>
> >
> > > Uprobes layer would need to be notified of process life-time events
> > > like fork/clone/exec/exit.
> >
> > No so much the process lifetimes as the vma life times are interesting,
> > placing a hook in the vm code to track that isn't too hard,
> >
> > > It also needs to know
> > > - when a breakpoint is hit
> > > - stop and resume a thread.
> >
> > A simple hook in the trap code is done quickly enough, and no reason to
> > stop the thread, its not going anywhere when it traps.
> >
> >
>
> Some of the threads could be executing in the vicinity of the
> breakpoint when it is getting inserted or deleted. Wont we need to
> stop/quiesce those threads?

The easy answer it so use kstopmachine to patch the code, the slightly
more complex would be using something like:

http://lkml.org/lkml/2010/1/12/300





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