Re: [(take 2)patch 6/7] Kprobes registers for notify page fault

Keshavamurthy Anil S
2006-04-21T01:06:29Z

On Fri, Apr 21, 2006 at 10:53:29AM +1000, Keith Owens wrote:
> Keshavamurthy Anil S (on Thu, 20 Apr 2006 17:38:47 -0700) wrote:
> >On Fri, Apr 21, 2006 at 10:14:04AM +1000, Keith Owens wrote:
> >> Anil S Keshavamurthy (on Thu, 20 Apr 2006 16:25:02 -0700) wrote:
> >> >---
> >> >@@ -654,6 +659,9 @@ static int __init init_kprobes(void)
> >> > if (!err)
> >> > err = register_die_notifier(&kprobe_exceptions_nb);
> >> >
> >> >+ if (!err)
> >> >+ err = register_page_fault_notifier(&kprobe_page_fault_nb);
> >> >+
> >> > return err;
> >> > }
> >> >
> >>
> >> The rest of the patches look OK, but this one does not. init_kprobes()
> >> registers the main kprobe exception handler, not the page fault
> >> handler.
> >I am registering for register_page_fault_notifier() and as you can see
> >I am not deleting the old register_die_notifier() which is also required
> >for getting notified on int3/break and single-step traps.
> >So no issues here.
>
> Patch 7 conditionally registers a page fault handler, plus an
> unregister when there are no user space probes. Why does patch 6
> unconditionally register a page fault handler?
Patch 7 is the improvement of patch 6, so in other words the patch
7 removes the patch 6's unconditional registration and adds
conditional registration support.

-Anil