Re: [PATCH v5] x86, cpu-hotplug: fix llc shared map unreleased during cpu hotplug

[Wanpeng Li]

ä 14-9-23 äå5:37, Borislav Petkov åé:
> On Wed, Sep 17, 2014 at 03:17:52PM +0800, Wanpeng Li 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
> >
> > This bug can be triggered by hot add and remove large number of xen
> > domain0's vcpus repeatedly.
> >
> > 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.
> >
> > Reviewed-by: Toshi Kani <toshi.kani@xxxxxx>
> > Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
> > Tested-by: Linn Crosetto <linn@xxxxxx>
> > Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
> Reviewed-by: Borislav Petkov <bp@xxxxxxx>

Thanks.


Ingo, Peter Z, HPA,


Could this patch catch up with 3.18 merge window?

Regards,
Wanpeng Li

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