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From: Michel Lespinasse <walken@google.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, Andrea Arcangeli <aarcange@redhat.com>,
	Rik van Riel <riel@redhat.com>, Dave Jones <davej@redhat.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH] mm, thp: close race between mremap() and split_huge_page()
Date: Wed, 7 May 2014 17:13:32 -0700	[thread overview]
Message-ID: <CANN689GqmdRpOOHV7uYCLgu+xKcYQ5_ESw7+-djNpVGo=D-+WQ@mail.gmail.com> (raw)
In-Reply-To: <20140506130655.GE19914@cmpxchg.org>

My bad for introducing the bug, and thanks Kirill for fixing it.

Acked-by: Michel Lespinasse <walken@google.com>

On Tue, May 6, 2014 at 6:06 AM, Johannes Weiner <hannes@cmpxchg.org> wrote:
> On Tue, May 06, 2014 at 01:13:31AM +0300, Kirill A. Shutemov wrote:
>> But on move_vma() destination VMA can be merged into adjacent one and as
>> result shifted left in interval tree. Fortunately, we can detect the
>> situation and prevent race with rmap walk by moving page table entries
>> under rmap lock. See commit 38a76013ad80.

Yup, forgot to take care of the THP case there...

> Fixes: 108d6642ad81 ("mm anon rmap: remove anon_vma_moveto_tail")

I think 108d6642ad81 on its own was OK (as it always took the locks);
but the attempt to not take them in the common case in 38a76013ad80 is
where I forgot to consider the THP case.

-- 
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.

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  reply	other threads:[~2014-05-08  0:13 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-05 22:13 Kirill A. Shutemov
2014-05-06  8:43 ` Kirill A. Shutemov
2014-05-07 20:55   ` David Miller
2014-05-06 13:06 ` Johannes Weiner
2014-05-08  0:13   ` Michel Lespinasse [this message]
2014-05-08 18:14     ` Johannes Weiner
2014-05-09  8:44       ` Michel Lespinasse
2014-05-06 14:13 ` Andrea Arcangeli

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