lkml.org 
[lkml]   [2010]   [Aug]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] perf: fix possible divide-by-zero in perf_swevent_overflow()
From
Date
On Fri, 2010-08-27 at 20:21 +0800, DDD wrote:

> >> Maybe the root cause was from kgdb/hw_breakpoint_layer,
> >
> > Yeah, I think there's a bug in the hw_breakpoint stuff, does something
> > like the below fix it?

> Thanks for your patch, but I still could reproduce the problem with your
> patch.

Frederic, any clue as to what makes hw breakpoints go funny and have
last_period == 0?

> > ---
> > kernel/hw_breakpoint.c | 13 ++++++++++++-
> > 1 files changed, 12 insertions(+), 1 deletions(-)
> >
> > diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
> > index d71a987..f57ebee 100644
> > --- a/kernel/hw_breakpoint.c
> > +++ b/kernel/hw_breakpoint.c
> > @@ -600,9 +600,20 @@ static int __init init_hw_breakpoint(void)
> > }
> > core_initcall(init_hw_breakpoint);
> >
> > +static int hw_breakpoint_enable(struct perf_event *event)
> > +{
> > + struct hw_perf_event *hwc = &event->hw;
> > +
> > + if (hwc->sample_period) {
> > + hwc->last_period = hwc->sample_period;
> > + perf_swevent_set_period(event);
> > + }
> > +
> > + return arch_install_hw_breakpoint(event);
> > +}
> >
> > struct pmu perf_ops_bp = {
> > - .enable = arch_install_hw_breakpoint,
> > + .enable = hw_breakpoint_enable,
> > .disable = arch_uninstall_hw_breakpoint,
> > .read = hw_breakpoint_pmu_read,
> > };
> >
> >


\
 
 \ /
  Last update: 2010-08-27 14:53    [W:0.047 / U:12.764 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site