On Wed, Jul 09, 2014 at 12:25:33PM +0530, Viresh Kumar wrote: > hrtimer_start*() family never fails to enqueue a hrtimer to a clock-base. The > only special case is when the hrtimer was in past. If it is getting enqueued > to > local CPUs's clock-base, we raise a softirq and exit, else we handle that on > next interrupt on remote CPU. > > At several places in kernel we check if hrtimer is enqueued properly with > hrtimer_active(). This isn't required and can be dropped. > > Before fixing that, lets make sure hrtimer is always enqueued properly by > adding > > WARN_ON_ONCE(!hrtimer_active(timer)); > > towards the end of __hrtimer_start_range_ns(). > > Suggested-by: Frederic Weisbecker <fweis...@gmail.com> > Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org> > --- > kernel/hrtimer.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c > index 3ab2899..cf40209 100644 > --- a/kernel/hrtimer.c > +++ b/kernel/hrtimer.c > @@ -1037,6 +1037,8 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, > ktime_t tim, > > unlock_hrtimer_base(timer, &flags); > > + /* Make sure timer is enqueued */ > + WARN_ON_ONCE(!hrtimer_active(timer));
Hmm, after reading Thomas reply, I think it's possible that the hrtimer expires right after we unlock it and, if we are unlucky enough, before the hrtimer_active() check. In this case we might hit a false positive. > return ret; > } > EXPORT_SYMBOL_GPL(__hrtimer_start_range_ns); > -- > 2.0.0.rc2 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
