| Date | Thu, 23 Jun 2022 06:14:01 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH 02/16] mm/huge_memory: access vm_page_prot with READ_ONCE in remove_migration_pmd |
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On Thu, Jun 23, 2022 at 01:06:13AM +0800, Miaohe Lin wrote: > vma->vm_page_prot is read lockless from the rmap_walk, it may be updated > concurrently. Using READ_ONCE to prevent the risk of reading intermediate > values.
Have you checked all other vm_page_prot reads that they hold mmap_lock?
I think the right fix would be to provide a helper to read vm_page_prot which does READ_ONCE() and use it everywhere. This seems more sustainable.
-- Kirill A. Shutemov
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