Merge branch 'for_rmk' of git://git.linaro.org/kernel/linux-linaro-next into devel-stable

1 files changed, 5 insertions, 3 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 71b161b73bb5..0e18b4d649ec 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2680,10 +2680,12 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
         delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
 
         /*
-         * Make sure try_to_free_swap didn't release the swapcache
-         * from under us. The page pin isn't enough to prevent that.
+         * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
+         * release the swapcache from under us.  The page pin, and pte_same
+         * test below, are not enough to exclude that.  Even if it is still
+         * swapcache, we need to check that the page's swap has not changed.
          */
-        if (unlikely(!PageSwapCache(page)))
+        if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val))
                 goto out_page;
 
         if (ksm_might_need_to_copy(page, vma, address)) {