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Ralph Campbell
8d63e4cd62
mm/hmm: fix uninitialized use of 'entry' in hmm_vma_walk_pmd()
The variable 'entry' is used before being initialized in hmm_vma_walk_pmd(). No bad effect (beside performance hit) so !non_swap_entry(0) evaluate to true which trigger a fault as if CPU was trying to access migrated memory and migrate memory back from device memory to regular memory. This function (hmm_vma_walk_pmd()) is called when a device driver tries to populate its own page table. For migrated memory it should not happen as the device driver should already have populated its page table correctly during the migration. Only case I can think of is multi-GPU where a second GPU triggers migration back to regular memory. Again this would just result in a performance hit, nothing bad would happen. Link: http://lkml.kernel.org/r/20180122185759.26286-1-jglisse@redhat.com Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.
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