Re: [PATCH] kprobes patch

["Keshavamurthy, Anil S" <anil dot s dot keshavamurthy at intel dot com>]

On Sat, Oct 28, 2006 at 10:21:05AM +0900, Jun Koi wrote:
> Hi Keshavanmurthy,
> 
> On 10/28/06, Keshavamurthy@bambi.jf.intel.com
> <Keshavamurthy@bambi.jf.intel.com> wrote:
> >On Sat, Oct 28, 2006 at 03:58:18AM +0900, Jun Koi wrote:
> >> Hello,
> >>
> >> I am not sure if this is a right place to send patch for kprobes, but
> >> here it is.  This patch moves the reset command of kprobe instance
> >> into the loop. (against 2.6.18)
> >
> >Hi jun,
> >Yes, you have sent it to the right place. thanks.
> >BTW, is is helpful to know what problem did you encounter due to which
> >you had come up with this patch. Or did you catch this bug by just code 
> >review?
> >
> 
> I had no problem at al. You are right, the patch is a result of
> reviewing the code.

Okay. Looked at your patch more carefully and found that there is
no bug as such. Please see my inline comments.

> 
> Best,
> Jun
> 
> >>
> >> Signed-off-by: Jun Koi <junkoi2004@gmail.com>
> >>
> >>
> >> --- a/kernel/kprobes.c    2006-09-20 12:42:06.000000000 +0900
> >> +++ b/kernel/kprobes.c        2006-10-28 03:52:27.000000000 +0900
> >> @@ -204,8 +204,8 @@ static int __kprobes aggr_pre_handler(st
> >>                        set_kprobe_instance(kp);
> >>                        if (kp->pre_handler(kp, regs))
> >>                                return 1;
> >> +                       reset_kprobe_instance();
> >>                }
> >> -               reset_kprobe_instance();

The reason that reset_kprobe_instance() is outside the loop is a kind of 
optimization.  You can call reset_kprobe_instance() once you are
out of the loop instead of having to call everytime inside the loop
followed  by immediate call to set_kprobe_instance().

> >>        }
> >>        return 0;
> >> }
> >

thanks,
Anil Keshavamurthy