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From: Jiang Liu <jiang.liu@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Tony Luck <tony.luck@intel.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [Bugfix] sched: fix possible invalid memory access caused by CPU hot-addition
Date: Wed, 23 Apr 2014 13:45:04 +0800	[thread overview]
Message-ID: <53575360.3010702@linux.intel.com> (raw)
In-Reply-To: <20140423053213.GV26782@laptop.programming.kicks-ass.net>

On 2014/4/23 13:32, Peter Zijlstra wrote:
> On Wed, Apr 23, 2014 at 10:45:13AM +0800, Jiang Liu wrote:
>> Hi Peter,
>> 	It's not for memoryless node, but to solve a race window
>> in CPU hot-addition. The related CPU hot-addition flow is:
>> 1) Handle CPU hot-addition event
>> 1.a) gather platform specific information
>> 1.b) associate hot-added CPU with a node
>> 1.c) create CPU device
>> 2) User online hot-added CPUs through sysfs:
>> 2.a)	cpu_up()
>> 2.b)		->try_online_node()
>> 2.c)			->hotadd_new_pgdat()
>> 2.d)			->node_set_online()
>>
>> So between 1.b and 2.c, kmalloc_node(nid) may cause invalid
>> memory access without the node_online(nid) check.
> 
> Any why was all this not in the Changelog?
Sorry, will add above message into changelog.
Thanks!
Gerry

  reply	other threads:[~2014-04-23  5:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-22  5:27 [Bugfix] sched: fix possible invalid memory access caused by CPU hot-addition Jiang Liu
2014-04-22  8:15 ` Peter Zijlstra
2014-04-22 20:01   ` Andrew Morton
2014-04-22 20:04     ` Peter Zijlstra
2014-04-23  1:59       ` David Rientjes
2014-04-23  4:53         ` Jiang Liu
2014-04-23  2:05       ` Mike Galbraith
2014-04-23  2:45   ` Jiang Liu
2014-04-23  5:32     ` Peter Zijlstra
2014-04-23  5:45       ` Jiang Liu [this message]
2014-04-23  5:51       ` Peter Zijlstra
2014-04-23 17:46         ` Luck, Tony
2014-04-24  2:59           ` Jiang Liu
2014-04-24  7:47             ` Peter Zijlstra
2014-04-24 17:41               ` Luck, Tony
2014-04-24 19:09                 ` Peter Zijlstra

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