Re: [PATCH v5 08/14] mm/gup: do not allow zero page for pinned pages

[PATCH v5 00/14] prohibit pinning pages in ZONE_MOVABLE · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 03/14] mm/gup: return an error on migration failure · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
Re: [PATCH v5 03/14] mm/gup: return an error on migration failure · Jason Gunthorpe <jgg@ziepe.ca> · 2021-01-19
[PATCH v5 04/14] mm/gup: check for isolation errors · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
Re: [PATCH v5 04/14] mm/gup: check for isolation errors · Jason Gunthorpe <jgg@ziepe.ca> · 2021-01-19
Re: [PATCH v5 04/14] mm/gup: check for isolation errors · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 09/14] mm/gup: migrate pinned pages out of movable zone · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 06/14] mm: apply per-task gfp constraints in fast path · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 10/14] memory-hotplug.rst: add a note about ZONE_MOVABLE and page pinning · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 08/14] mm/gup: do not allow zero page for pinned pages · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
Re: [PATCH v5 08/14] mm/gup: do not allow zero page for pinned pages · Jason Gunthorpe <jgg@ziepe.ca> · 2021-01-19
Re: [PATCH v5 08/14] mm/gup: do not allow zero page for pinned pages · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
Re: [PATCH v5 08/14] mm/gup: do not allow zero page for pinned pages · Jason Gunthorpe <jgg@ziepe.ca> · 2021-01-19
Re: [PATCH v5 08/14] mm/gup: do not allow zero page for pinned pages · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
Re: [PATCH v5 08/14] mm/gup: do not allow zero page for pinned pages · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
Re: [PATCH v5 08/14] mm/gup: do not allow zero page for pinned pages · Jason Gunthorpe <jgg@ziepe.ca> · 2021-01-19
[PATCH v5 01/14] mm/gup: don't pin migrated cma pages in movable zone · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 07/14] mm: honor PF_MEMALLOC_PIN for all movable pages · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 11/14] mm/gup: change index type to long as it counts pages · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 14/14] selftests/vm: test faulting in kernel, and verify pinnable pages · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 13/14] selftests/vm: test flag is broken · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 12/14] mm/gup: longterm pin migration cleaup · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 05/14] mm cma: rename PF_MEMALLOC_NOCMA to PF_MEMALLOC_PIN · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
[PATCH v5 02/14] mm/gup: check every subpage of a compound page during isolation · Pavel Tatashin <pasha.tatashin@soleen.com> · 2021-01-19
Re: [PATCH v5 02/14] mm/gup: check every subpage of a compound page during isolation · Jason Gunthorpe <jgg@ziepe.ca> · 2021-01-19

From: Jason Gunthorpe <jgg@ziepe.ca>
Date: 2021-01-19 23:43:44
Also in: linux-kselftest, linux-mm, lkml

On Tue, Jan 19, 2021 at 03:14:04PM -0500, Pavel Tatashin wrote:

I was thinking about a use case where userland would pin an address
without FOLL_WRITE, because the PTE for that address is not going to
be writable, but some device via DMA will write to it.

That would be a serious bug in the get_user_pages caller to write to a
page without using FOLL_WRITE

Jason

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