Message-ID: <53D100A2.3090404@oracle.com>
Date: Thu, 24 Jul 2014 08:48:34 -0400
From: Sasha Levin <sasha.levin@oracle.com>
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To: Andrey Ryabinin <a.ryabinin@samsung.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@redhat.com>
CC: Andi Kleen <ak@linux.intel.com>,
        Matthew Wilcox <matthew.r.wilcox@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Dave Chinner <david@fromorbit.com>, Ning Qu <quning@gmail.com>,
        linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, Dave Jones <davej@redhat.com>,
        Konstantin Khlebnikov <koct9i@gmail.com>
Subject: Re: [PATCHv3 1/2] mm: introduce vm_ops->map_pages()
References: <1393530827-25450-1-git-send-email-kirill.shutemov@linux.intel.com> <1393530827-25450-2-git-send-email-kirill.shutemov@linux.intel.com> <53D07E96.5000006@oracle.com> <53D0AD7E.3050705@samsung.com>
In-Reply-To: <53D0AD7E.3050705@samsung.com>
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Sender: linux-kernel-owner@vger.kernel.org

On 07/24/2014 02:53 AM, Andrey Ryabinin wrote:
> On 07/24/14 07:33, Sasha Levin wrote:
>> > On 02/27/2014 02:53 PM, Kirill A. Shutemov wrote:
>>> >> The patch introduces new vm_ops callback ->map_pages() and uses it for
>>> >> mapping easy accessible pages around fault address.
>>> >>
>>> >> On read page fault, if filesystem provides ->map_pages(), we try to map
>>> >> up to FAULT_AROUND_PAGES pages around page fault address in hope to
>>> >> reduce number of minor page faults.
>>> >>
>>> >> We call ->map_pages first and use ->fault() as fallback if page by the
>>> >> offset is not ready to be mapped (cold page cache or something).
>>> >>
>>> >> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
>>> >> ---
>> > 
>> > Hi all,
>> > 
>> > This patch triggers use-after-free when fuzzing using trinity and the KASAN
>> > patchset.
>> > 
> I think this should be fixed already by following patch:
> 
> From: Konstantin Khlebnikov <koct9i@gmail.com>
> Subject: mm: do not call do_fault_around for non-linear fault

I don't think so. It's supposed to deal with a different issue, and it was already
in my -next tree which triggered the issue I've reported.


Thanks,
Sasha
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