Re: [PATCHv3 1/2] mm: introduce vm_ops->map_pages()

[Sasha Levin]

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@xxxxxxxxxxxxxxx>
>>> >> ---
>> > 
>> > 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@xxxxxxxxx>
> 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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