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| author | Peter Feiner <pfeiner@google.com> | 2014-09-25 16:05:29 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-10-05 14:52:21 -0700 |
| commit | 3e272e4fe150d565189c1558e51fdf6e801c97ce (patch) | |
| tree | 727c961eb6b30e954e18c0c4a0935dfec98c3027 | |
| parent | 168e7c5696a1bed56c3d52ebef97a280e404daaf (diff) | |
| download | lwn-3e272e4fe150d565189c1558e51fdf6e801c97ce.tar.gz lwn-3e272e4fe150d565189c1558e51fdf6e801c97ce.zip | |
mm: softdirty: keep bit when zapping file pte
commit dbab31aa2ceec2d201966fa0b552f151310ba5f4 upstream.
This fixes the same bug as b43790eedd31 ("mm: softdirty: don't forget to
save file map softdiry bit on unmap") and 9aed8614af5a ("mm/memory.c:
don't forget to set softdirty on file mapped fault") where the return
value of pte_*mksoft_dirty was being ignored.
To be sure that no other pte/pmd "mk" function return values were being
ignored, I annotated the functions in arch/x86/include/asm/pgtable.h
with __must_check and rebuilt.
The userspace effect of this bug is that the softdirty mark might be
lost if a file mapped pte get zapped.
Signed-off-by: Peter Feiner <pfeiner@google.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Jamie Liu <jamieliu@google.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | mm/memory.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c index 2121d8b8db56..492e36f27f43 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1120,7 +1120,7 @@ again: addr) != page->index) { pte_t ptfile = pgoff_to_pte(page->index); if (pte_soft_dirty(ptent)) - pte_file_mksoft_dirty(ptfile); + ptfile = pte_file_mksoft_dirty(ptfile); set_pte_at(mm, addr, pte, ptfile); } if (PageAnon(page)) |