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-rw-r--r--mm/memory.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 71b161b..0e18b4d 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)) {
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