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Message-ID: <54227E6F.6080707@gmail.com>
Date: Wed, 24 Sep 2014 16:18:55 +0800
From: Wanpeng Li <kernellwp@gmail.com>
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To: Ingo Molnar <mingo@kernel.org>
CC: Borislav Petkov <bp@alien8.de>, Wanpeng Li <wanpeng.li@linux.intel.com>,
        Ingo Molnar <mingo@redhat.com>, hpa@zytor.com,
        Peter Zijlstra <peterz@infradead.org>, x86@kernel.org,
        Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
        David Rientjes <rientjes@google.com>,
        Prarit Bhargava <prarit@redhat.com>,
        Steven Rostedt <srostedt@redhat.com>, Toshi Kani <toshi.kani@hp.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5] x86, cpu-hotplug: fix llc shared map unreleased during
 cpu hotplug
References: <1410938272-7217-1-git-send-email-wanpeng.li@linux.intel.com> <20140923093753.GA22644@pd.tnic> <542206DB.9080102@gmail.com> <20140924075210.GC3797@gmail.com>
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于 9/24/14, 3:52 PM, Ingo Molnar 写道:
> * Wanpeng Li <kernellwp@gmail.com> wrote:
>
>> 于 14-9-23 下午5:37, Borislav Petkov 写道:
>>> 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@hp.com>
>>>> Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>>> Tested-by: Linn Crosetto <linn@hp.com>
>>>> Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
>>> Reviewed-by: Borislav Petkov <bp@suse.de>
>>>
>> 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