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SubjectRe: [PATCH v4] x86, hotplug: fix llc shared map unreleased during cpu hotplug
于 14-9-16 下午5:01, Ingo Molnar 写道:
> * Wanpeng Li <wanpeng.li@linux.intel.com> wrote:
>
>> 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? ;-)
> Please send a fresh new version, maintainers trying to splice &
> dice patches and changelogs is an unrobust approach prone to
> mistakes.

Ok, I will send out a new version tomorrow. ;-)

Regards,
Wanpeng Li

>
> Thanks,
>
> Ingo
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