1 files changed, 9 insertions, 1 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index e07e27e846a2..a9963ceddd65 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1176,7 +1176,15 @@ static inline unsigned interleave_nid(struct mempolicy *pol,
         if (vma) {
                 unsigned long off;
 
-                off = vma->vm_pgoff;
+                /*
+                 * for small pages, there is no difference between
+                 * shift and PAGE_SHIFT, so the bit-shift is safe.
+                 * for huge pages, since vm_pgoff is in units of small
+                 * pages, we need to shift off the always 0 bits to get
+                 * a useful offset.
+                 */
+                BUG_ON(shift < PAGE_SHIFT);
+                off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
                 off += (addr - vma->vm_start) >> shift;
                 return offset_il_node(pol, vma, off);
         } else