Messages in this thread | | | From | "Aneesh Kumar K.V" <> | Subject | Re: [PATCHv3 1/2] mm/gup: fix omission of check on FOLL_LONGTERM in get_user_pages_fast() | Date | Tue, 11 Jun 2019 21:45:31 +0530 |
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Pingfan Liu <kernelfans@gmail.com> writes:
> As for FOLL_LONGTERM, it is checked in the slow path > __gup_longterm_unlocked(). But it is not checked in the fast path, which > means a possible leak of CMA page to longterm pinned requirement through > this crack.
Shouldn't we disallow FOLL_LONGTERM with get_user_pages fastpath? W.r.t dax check we need vma to ensure whether a long term pin is allowed or not. If FOLL_LONGTERM is specified we should fallback to slow path.
-aneesh
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