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From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>,
	Kirill Tkhai <ktkhai@parallels.com>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Vladimir Davydov <vdavydov@parallels.com>,
	cl@linux.com
Subject: Re: [PATCH v3] sched/numa: fix unsafe get_task_struct() in task_numa_assign()
Date: Wed, 22 Oct 2014 18:37:43 +0200	[thread overview]
Message-ID: <20141022163743.GI21513@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20141022161450.GA27607@redhat.com>

On Wed, Oct 22, 2014 at 06:14:50PM +0200, Oleg Nesterov wrote:
> Hmm. so perhaps I misunderstood your concern...
> 
> Do you mean that on !x86 a plain LOAD can "corrupt" the memory as it seen
> from another vaddr?

I'm not sure. Stores for sure, loads I'm not sure about.

I suspect loads are OK, the aliasing cacheline will be !modified and
therefore later eviction should discard (not write back). But like said,
I'm not at all sure.

I would hesitate to put such assumptions into generic code -- although
it appears we already have.

  reply	other threads:[~2014-10-22 16:37 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-20 10:15 Kirill Tkhai
2014-10-20 14:47 ` Oleg Nesterov
2014-10-20 16:56   ` Oleg Nesterov
2014-10-20 18:27     ` Oleg Nesterov
2014-10-20 20:18       ` Kirill Tkhai
2014-10-20 20:50         ` Oleg Nesterov
2014-10-20 21:05           ` Kirill Tkhai
2014-10-20 21:34             ` Oleg Nesterov
2014-10-20 22:57               ` Peter Zijlstra
2014-10-21  9:45           ` Peter Zijlstra
2014-10-21 19:03             ` Oleg Nesterov
2014-10-21 20:03               ` Kirill Tkhai
2014-10-21 20:10                 ` Kirill Tkhai
2014-10-22  9:09               ` Peter Zijlstra
2014-10-22 16:14                 ` Oleg Nesterov
2014-10-22 16:37                   ` Peter Zijlstra [this message]
2014-10-22 18:14                     ` introduce probe_slab_address? (Was: sched/numa: fix unsafe get_task_struct() in task_numa_assign()) Oleg Nesterov
2014-10-22 18:59                       ` introduce probe_slab_address? David Miller
2014-10-22 19:42                         ` Oleg Nesterov
2014-10-22 20:08                           ` David Miller
2014-10-22 20:20                             ` Oleg Nesterov
2014-10-24  9:44                         ` Peter Zijlstra

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