The patch titled
Subject: mm/rmap: fix new bug: premature return from page_mlock_one()
has been added to the -mm tree. Its filename is
mm-rmap-fix-new-bug-premature-return-from-page_mlock_one.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-rmap-fix-new-bug-premature-return-from-page_mlock_one.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-rmap-fix-new-bug-premature-return-from-page_mlock_one.patch
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: mm/rmap: fix new bug: premature return from page_mlock_one()
In the unlikely race case that page_mlock_one() finds VM_LOCKED has been
cleared by the time it got page table lock, page_vma_mapped_walk_done()
must be called before returning, either explicitly, or by a final call to
page_vma_mapped_walk() - otherwise the page table remains locked.
Link: https://lkml.kernel.org/r/f71f8523-cba7-3342-40a7-114abc5d1f51@xxxxxxxxxx
Fixes: cd62734ca60d ("mm/rmap: split try_to_munlock from try_to_unmap")
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Reviewed-by: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/rmap.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
--- a/mm/rmap.c~mm-rmap-fix-new-bug-premature-return-from-page_mlock_one
+++ a/mm/rmap.c
@@ -1991,14 +1991,13 @@ static bool page_mlock_one(struct page *
* after DoubleMap was cleared).
*/
mlock_vma_page(page);
+ /*
+ * No need to scan further once the page is marked
+ * as mlocked.
+ */
page_vma_mapped_walk_done(&pvmw);
+ return false;
}
-
- /*
- * no need to continue scanning other vma's if the page has
- * been locked.
- */
- return false;
}
return true;
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
mm-rmap-fix-comments-left-over-from-recent-changes.patch
mm-rmap-fix-old-bug-munlocking-thp-missed-other-mlocks.patch
mm-rmap-fix-new-bug-premature-return-from-page_mlock_one.patch
mm-rmap-try_to_migrate-skip-zone_device-device_private.patch
fs-mm-fix-race-in-unlinking-swapfile.patch
