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096cbb80ab
Ever since commitb756a3b5e7("mm: device exclusive memory access") we can return with a device-exclusive entry from page_vma_mapped_walk(). __replace_page() is not prepared for that, so teach it about these PFN swap PTEs. Note that device-private entries are so far not applicable on that path, because GUP would never have returned such folios (conversion to device-private happens by page migration, not in-place conversion of the PTE). There is a race between GUP and us locking the folio to look it up using page_vma_mapped_walk(), so this is likely a fix (unless something else could prevent that race, but it doesn't look like). pte_pfn() on something that is not a present pte could give use garbage, and we'd wrongly mess up the mapcount because it was already adjusted by calling folio_remove_rmap_pte() when making the entry device-exclusive. Link: https://lkml.kernel.org/r/20250210193801.781278-9-david@redhat.com Fixes:b756a3b5e7("mm: device exclusive memory access") Signed-off-by: David Hildenbrand <david@redhat.com> Tested-by: Alistair Popple <apopple@nvidia.com> Cc: Alex Shi <alexs@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dave Airlie <airlied@gmail.com> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Karol Herbst <kherbst@redhat.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Lyude <lyude@redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Simona Vetter <simona.vetter@ffwll.ch> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yanteng Si <si.yanteng@linux.dev> Cc: Barry Song <v-songbaohua@oppo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.