The patch titled
Subject: mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk()
has been added to the -mm tree. Its filename is
mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk.patch
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx
Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()")
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Wang Yugui <wangyugui@xxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_vma_mapped.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/mm/page_vma_mapped.c~mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk
+++ a/mm/page_vma_mapped.c
@@ -277,6 +277,10 @@ 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) {
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry.patch
mm-thp-make-is_huge_zero_pmd-safe-and-quicker.patch
mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting.patch
mm-thp-fix-vma_address-if-virtual-address-below-file-offset.patch
mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page.patch
mm-page_vma_mapped_walk-use-page-for-pvmw-page.patch
mm-page_vma_mapped_walk-settle-pagehuge-on-entry.patch
mm-page_vma_mapped_walk-use-pmd_read_atomic.patch
mm-page_vma_mapped_walk-use-pmde-for-pvmw-pmd.patch
mm-page_vma_mapped_walk-prettify-pvmw_migration-block.patch
mm-page_vma_mapped_walk-crossing-page-table-boundary.patch
mm-page_vma_mapped_walk-add-a-level-of-indentation.patch
mm-page_vma_mapped_walk-use-goto-instead-of-while-1.patch
mm-page_vma_mapped_walk-get-vma_address_end-earlier.patch
mm-thp-fix-page_vma_mapped_walk-if-thp-mapped-by-ptes.patch
mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk.patch
mm-thp-remap_page-is-only-needed-on-anonymous-thp.patch
mm-hwpoison_user_mappings-try_to_unmap-with-ttu_sync.patch
