From: Wanpeng Li <wanpeng.li@linux.intel.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: hpa@zytor.com, Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
x86@kernel.org, Borislav Petkov <bp@alien8.de>,
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
David Rientjes <rientjes@google.com>,
Prarit Bhargava <prarit@redhat.com>,
Steven Rostedt <srostedt@redhat.com>,
Jan Kiszka <jan.kiszka@siemens.com>,
Toshi Kani <toshi.kani@hp.com>,
linux-kernel@vger.kernel.org, Zhang Yang <yang.z.zhang@intel.com>,
Wanpeng Li <wanpeng.li@linux.intel.com>
Subject: Re: [PATCH v4] x86, hotplug: fix llc shared map unreleased during cpu hotplug
Date: Thu, 4 Sep 2014 16:56:41 +0800 [thread overview]
Message-ID: <20140904085641.GA6311@kernel> (raw)
In-Reply-To: <20140904052034.GA29146@gmail.com>
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.
Regards,
Wanpeng Li
>
>Thanks,
>
> Ingo
next prev parent reply other threads:[~2014-09-04 8:55 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-29 9:24 [PATCH v4] x86, hotplug: fix llc shared map unreleased during cpu hotplug Wanpeng Li
2014-07-29 17:18 ` Toshi Kani
2014-08-07 6:33 ` Wanpeng Li
[not found] ` <20140808224057.GA9288@oranje.fc.hp.com>
2014-08-15 3:00 ` Wanpeng Li
2014-08-15 6:07 ` Borislav Petkov
2014-08-25 5:32 ` Wanpeng Li
2014-09-04 1:46 ` Wanpeng Li
2014-09-04 5:20 ` Ingo Molnar
2014-09-04 5:40 ` Yasuaki Ishimatsu
2014-09-04 6:24 ` Peter Zijlstra
2014-09-04 9:02 ` Wanpeng Li
2014-09-04 8:56 ` Wanpeng Li [this message]
2014-09-04 9:34 ` Wanpeng Li
2014-09-15 1:32 ` Wanpeng Li
2014-09-16 9:01 ` Ingo Molnar
2014-09-16 10:00 ` Wanpeng Li
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