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

[Wanpeng Li]

ä 9/24/14, 3:52 PM, Ingo Molnar åé:
> * Wanpeng Li <kernellwp@xxxxxxxxx> wrote:
>
> > 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?
> Please also add the real-hardware reports to the changelog.

Just send out the latest version.

Regards,
Wanpeng Li

> Thanks,
>
> 	Ingo

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