From: Dave Hansen <dave.hansen@intel.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>
Cc: Nadia Yvette Chambers <nyc@holomorphy.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Matthew Wilcox <willy@linux.intel.com>
Subject: Re: [PATCH] x86, mm: get ASLR work for hugetlb mappings
Date: Tue, 22 Oct 2013 08:21:25 -0700 [thread overview]
Message-ID: <526697F5.7040800@intel.com> (raw)
In-Reply-To: <1382449940-24357-1-git-send-email-kirill.shutemov@linux.intel.com>
On 10/22/2013 06:52 AM, Kirill A. Shutemov wrote:
> Matthew noticed that hugetlb doesn't participate in ASLR on x86-64.
> The reason is genereic hugetlb_get_unmapped_area() which is used on
> x86-64. It doesn't support randomization and use bottom-up unmapped area
> lookup, instead of usual top-down on x86-64.
I have to wonder if this was on purpose in order to keep the large and
small mappings separate. We don't *have* to keep them separate this, of
course, but it makes me wonder.
> x86 has arch-specific hugetlb_get_unmapped_area(), but it's used only on
> x86-32.
>
> Let's use arch-specific hugetlb_get_unmapped_area() on x86-64 too.
> It fixes the issue and make hugetlb use top-down unmapped area lookup.
Shouldn't we fix the generic code instead of further specializing the
x86 stuff?
In any case, you probably also want to run this through: the
libhugetlbfs tests:
http://sourceforge.net/p/libhugetlbfs/code/ci/master/tree/tests/
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next prev parent reply other threads:[~2013-10-22 15:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-22 13:52 [PATCH] x86, mm: get ASLR work for hugetlb mappings Kirill A. Shutemov
2013-10-22 15:21 ` Dave Hansen [this message]
2013-10-22 17:52 ` Kirill A. Shutemov
2013-11-04 10:41 ` Kirill A. Shutemov
2013-11-04 21:09 ` Andrew Morton
2013-11-11 13:45 ` Kirill A. Shutemov
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