Re: [3/3 PATCH] Kprobes: User space probes support- single stepping out-of-line

Arjan van de Ven
2006-03-20T14:14:15Z

On Mon, 2006-03-20 at 19:35 +0530, Prasanna S Panchamukhi wrote:
> On Mon, Mar 20, 2006 at 12:24:01PM +0100, Arjan van de Ven wrote:
> >
> > Lines: 16
> >
> > > And we'll need to actually *be* in-atomic. That means we need an
> > > open-coded inc_preempt_count() and dec_preempt_count() in there and I don't
> > > see them.
> > >
> >
> > ..
> >
> > > Why is VM_LOCKED being set? (It needs a comment).
> > >
> > > Where does it get unset?
> >
> >
> > if this is an attempt to make the copy_in_atomic to be atomic, then it
> > is a bug; the user can unset this bit after all via mprotect, even from
> > another thread, and concurrently. U
>
> You are right, the purpose was to make copy_to_user_inatomic() to suceed. I
> need to look at this issue again. Any suggestions?

get_user_pages seems to be the only viable API for this..