On Tue, Nov 19, 2013 at 03:36:12PM -0800, Yinghai Lu wrote: > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -5379,10 +5379,31 @@ void update_group_power(struct sched_domain *sd, int cpu) > > */ > > > > for_each_cpu(cpu, sched_group_cpus(sdg)) { > > - struct sched_group *sg = cpu_rq(cpu)->sd->groups; > > + struct sched_group_power *sgp; > > + struct rq *rq = cpu_rq(cpu); > > > > - power_orig += sg->sgp->power_orig; > > - power += sg->sgp->power; > > + /* > > + * build_sched_domains() -> init_sched_groups_power() > > + * gets here before we've attached the domains to the > > + * runqueues. > > + * > > + * Use power_of(), which is set irrespective of domains > > + * in update_cpu_power(). > > + * > > + * This avoids power/power_orig from being 0 and > > + * causing divide-by-zero issues on boot. > > + * > > + * Runtime updates will correct power_orig. > > + */ > > + if (unlikely(!rq->sd)) { > > + power_orig += power_of(cpu); > > + power += power_of(cpu); > > + continue; > > + } > > + > > + sgp = rq->sd->groups->sgp; > > + power_orig += sgp->power_orig; > > + power += sgp->power; > > } > > } else { > > /* > > This one seems fix NULL reference in compute_group_power. > > but get following on current Linus tree plus tip/sched/urgent. > > divide error: 0000 [#1] SMP > [ 28.190477] Modules linked in: > [ 28.192012] CPU: 11 PID: 484 Comm: kworker/u324:0 Not tainted > 3.12.0-yh-10487-g4b94e59-dirty #2044 > [ 28.210488] Hardware name: Oracle Corporation Sun Fire > [ 28.229877] task: ffff88ff25205140 ti: ffff88ff2520a000 task.ti: > ffff88ff2520a000 > [ 28.236139] RIP: 0010:[<ffffffff810d9ff4>] [<ffffffff810d9ff4>] > find_busiest_group+0x2b4/0x8a0 Hurmph.. what kind of hardware is that? and is there anything funny you do to make it do this? -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html