1 files changed, 20 insertions, 4 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index eaa7a09eb72e..526704e8215d 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -182,7 +182,7 @@ int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src)
 {
         struct anon_vma_chain *avc, *pavc;
 
-        list_for_each_entry(pavc, &src->anon_vma_chain, same_vma) {
+        list_for_each_entry_reverse(pavc, &src->anon_vma_chain, same_vma) {
                 avc = anon_vma_chain_alloc();
                 if (!avc)
                         goto enomem_failure;
@@ -730,13 +730,29 @@ void page_move_anon_rmap(struct page *page,
  * @page:       the page to add the mapping to
  * @vma:        the vm area in which the mapping is added
  * @address:    the user virtual address mapped
+ * @exclusive:  the page is exclusively owned by the current process
  */
 static void __page_set_anon_rmap(struct page *page,
-        struct vm_area_struct *vma, unsigned long address)
+        struct vm_area_struct *vma, unsigned long address, int exclusive)
 {
         struct anon_vma *anon_vma = vma->anon_vma;
 
         BUG_ON(!anon_vma);
+
+        /*
+         * If the page isn't exclusively mapped into this vma,
+         * we must use the _oldest_ possible anon_vma for the
+         * page mapping!
+         *
+         * So take the last AVC chain entry in the vma, which is
+         * the deepest ancestor, and use the anon_vma from that.
+         */
+        if (!exclusive) {
+                struct anon_vma_chain *avc;
+                avc = list_entry(vma->anon_vma_chain.prev, struct anon_vma_chain, same_vma);
+                anon_vma = avc->anon_vma;
+        }
+
         anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
         page->mapping = (struct address_space *) anon_vma;
         page->index = linear_page_index(vma, address);
@@ -791,7 +807,7 @@ void page_add_anon_rmap(struct page *page,
         VM_BUG_ON(!PageLocked(page));
         VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
         if (first)
-                __page_set_anon_rmap(page, vma, address);
+                __page_set_anon_rmap(page, vma, address, 0);
         else
                 __page_check_anon_rmap(page, vma, address);
 }
@@ -813,7 +829,7 @@ void page_add_new_anon_rmap(struct page *page,
         SetPageSwapBacked(page);
         atomic_set(&page->_mapcount, 0); /* increment count (starts at -1) */
         __inc_zone_page_state(page, NR_ANON_PAGES);
-        __page_set_anon_rmap(page, vma, address);
+        __page_set_anon_rmap(page, vma, address, 1);
         if (page_evictable(page, vma))
                 lru_cache_add_lru(page, LRU_ACTIVE_ANON);
         else