Re: [PATCH v4] x86, hotplug: fix llc shared map unreleased during cpu hotplug

[Wanpeng Li <kernellwp@gmail.com>]

Ping Ingo, HPA, PeterZ
于 14-9-4 下午5:34, Wanpeng Li 写道:
> Hi Ingo,
> On Thu, Sep 04, 2014 at 04:56:41PM +0800, Wanpeng Li wrote:
>> On Thu, Sep 04, 2014 at 07:20:34AM +0200, Ingo Molnar wrote:
>>> * Wanpeng Li <wanpeng.li@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.
>>
> If I need to send a new version of the patch or you can pick the patch
> w/ the updated changelog for me? ;-)
>
> Regards,
> Wanpeng Li
>
>> Regards,
>> Wanpeng Li
>>
>>> Thanks,
>>>
>>> 	Ingo
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