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    Subject[104/107] vm: fix vm_pgoff wrap in upward expansion
    2.6.32-longterm review patch.  If anyone has any objections, please let us know.

    ------------------

    From: Hugh Dickins <hughd@google.com>

    commit 42c36f63ac1366ab0ecc2d5717821362c259f517 upstream.

    Commit a626ca6a6564 ("vm: fix vm_pgoff wrap in stack expansion") fixed
    the case of an expanding mapping causing vm_pgoff wrapping when you had
    downward stack expansion. But there was another case where IA64 and
    PA-RISC expand mappings: upward expansion.

    This fixes that case too.

    Signed-off-by: Hugh Dickins <hughd@google.com>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    mm/mmap.c | 9 ++++++---
    1 file changed, 6 insertions(+), 3 deletions(-)

    --- a/mm/mmap.c
    +++ b/mm/mmap.c
    @@ -1636,9 +1636,12 @@ int expand_upwards(struct vm_area_struct
    size = address - vma->vm_start;
    grow = (address - vma->vm_end) >> PAGE_SHIFT;

    - error = acct_stack_growth(vma, size, grow);
    - if (!error)
    - vma->vm_end = address;
    + error = -ENOMEM;
    + if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
    + error = acct_stack_growth(vma, size, grow);
    + if (!error)
    + vma->vm_end = address;
    + }
    }
    anon_vma_unlock(vma);
    return error;



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