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authorHugh Dickins <hughd@google.com>2021-06-24 18:39:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-24 19:40:53 -0700
commita7a69d8ba88d8dcee7ef00e91d413a4bd003a814 (patch)
tree31e5fe7533a654e098d37c62bd508bca14dc49af
parenta9a7504d9beaf395481faa91e70e2fd08f7a3dde (diff)
mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk()
Aha! Shouldn't that quick scan over pte_none()s make sure that it holds ptlock in the PVMW_SYNC case? That too might have been responsible for BUGs or WARNs in split_huge_page_to_list() or its unmap_page(), though I've never seen any. Link: https://lkml.kernel.org/r/1bdf384c-8137-a149-2a1e-475a4791c3c@google.com Link: https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/ Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()") Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Wang Yugui <wangyugui@e16-tech.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/page_vma_mapped.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index a4e962b510c7..a4435311754b 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -276,6 +276,10 @@ next_pte:
goto restart;
}
pvmw->pte++;
+ if ((pvmw->flags & PVMW_SYNC) && !pvmw->ptl) {
+ pvmw->ptl = pte_lockptr(mm, pvmw->pmd);
+ spin_lock(pvmw->ptl);
+ }
} while (pte_none(*pvmw->pte));
if (!pvmw->ptl) {