From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Naoya Horiguchi <nao.horiguchi@gmail.com>
Subject: Re: [PATCH 2/3] mm/hugetlb: take refcount under page table lock in follow_huge_pmd()
Date: Mon, 28 Jul 2014 21:10:18 -0400 [thread overview]
Message-ID: <20140729011018.GA25865@nhori.redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1407281602050.8998@chino.kir.corp.google.com>
On Mon, Jul 28, 2014 at 04:02:31PM -0700, David Rientjes wrote:
> On Mon, 28 Jul 2014, Naoya Horiguchi wrote:
>
> > We have a race condition between move_pages() and freeing hugepages,
> > where move_pages() calls follow_page(FOLL_GET) for hugepages internally
> > and tries to get its refcount without preventing concurrent freeing.
> > This race crashes the kernel, so this patch fixes it by moving FOLL_GET
> > code for hugepages into follow_huge_pmd() with taking the page table lock.
> >
>
> What about CONFIG_ARCH_WANT_GENERAL_HUGETLB=n configs?
Ah yes, I need cover them.
So I'll add some wrapper to do this locking in common hugetlb code.
Thanks,
Naoya Horiguchi
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next prev parent reply other threads:[~2014-07-29 2:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-28 18:08 [PATCH 1/3] mm/hugetlb: replace parameters of follow_huge_pmd/pud() Naoya Horiguchi
2014-07-28 18:08 ` [PATCH 2/3] mm/hugetlb: take refcount under page table lock in follow_huge_pmd() Naoya Horiguchi
2014-07-28 23:02 ` David Rientjes
2014-07-29 1:10 ` Naoya Horiguchi [this message]
2014-07-28 18:08 ` [PATCH 3/3] mm/hugetlb: use get_page_unless_zero() in hugetlb_fault() Naoya Horiguchi
2014-07-28 22:55 ` [PATCH 1/3] mm/hugetlb: replace parameters of follow_huge_pmd/pud() David Rientjes
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