On Thu, Sep 04, 2014 at 07:20:34AM +0200, Ingo Molnar wrote: > >* Wanpeng Li <wanpeng...@linux.intel.com> wrote: > >> BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 >> IP: [..] find_busiest_group >> PGD 5a9d5067 PUD 13067 PMD 0 >> Oops: 0000 [#3] SMP >> [...] >> Call Trace: >> load_balance >> ? _raw_spin_unlock_irqrestore >> idle_balance >> __schedule >> schedule >> schedule_timeout >> ? lock_timer_base >> schedule_timeout_uninterruptible >> msleep >> lock_device_hotplug_sysfs >> online_store >> dev_attr_store >> sysfs_write_file >> vfs_write >> SyS_write >> system_call_fastpath >> >> Last level cache shared map is built during cpu up and build sched domain >> routine takes advantage of it to setup sched domain cpu topology, however, >> llc shared map is unreleased during cpu disable which lead to invalid sched >> domain cpu topology. This patch fix it by release llc shared map correctly >> during cpu disable. > >Very little is said in this changelog about how the bug was >found, how likely it is to occur for others, what systems are >affected, etc.
This bug can be triggered by hot add and remove large number of xen domain0's vcpus repeated. Regards, Wanpeng Li > >Thanks, > > Ingo -- 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/
