3 files changed, 27 insertions, 19 deletions

diff --git a/mm/fremap.c b/mm/fremap.c
index 46f5dacf90a2..ec520c7b28df 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -125,7 +125,6 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
 {
         struct mm_struct *mm = current->mm;
         struct address_space *mapping;
-        unsigned long end = start + size;
         struct vm_area_struct *vma;
         int err = -EINVAL;
         int has_write_lock = 0;
@@ -142,6 +141,10 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
         if (start + size <= start)
                 return err;
 
+        /* Does pgoff wrap? */
+        if (pgoff + (size >> PAGE_SHIFT) < pgoff)
+                return err;
+
         /* Can we represent this offset inside this architecture's pte's? */
 #if PTE_FILE_MAX_BITS < BITS_PER_LONG
         if (pgoff + (size >> PAGE_SHIFT) >= (1UL << PTE_FILE_MAX_BITS))
@@ -168,7 +171,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
         if (!(vma->vm_flags & VM_CAN_NONLINEAR))
                 goto out;
 
-        if (end <= start || start < vma->vm_start || end > vma->vm_end)
+        if (start < vma->vm_start || start + size > vma->vm_end)
                 goto out;
 
         /* Must set VM_NONLINEAR before any pages are populated. */
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index cc5be788a39f..c03273807182 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2324,11 +2324,8 @@ retry_avoidcopy:
          * and just make the page writable */
         avoidcopy = (page_mapcount(old_page) == 1);
         if (avoidcopy) {
-                if (!trylock_page(old_page)) {
-                        if (PageAnon(old_page))
-                                page_move_anon_rmap(old_page, vma, address);
-                } else
-                        unlock_page(old_page);
+                if (PageAnon(old_page))
+                        page_move_anon_rmap(old_page, vma, address);
                 set_huge_ptep_writable(vma, address, ptep);
                 return 0;
         }
@@ -2404,7 +2401,7 @@ retry_avoidcopy:
                 set_huge_pte_at(mm, address, ptep,
                                 make_huge_pte(vma, new_page, 1));
                 page_remove_rmap(old_page);
-                hugepage_add_anon_rmap(new_page, vma, address);
+                hugepage_add_new_anon_rmap(new_page, vma, address);
                 /* Make the old page be freed below */
                 new_page = old_page;
                 mmu_notifier_invalidate_range_end(mm,
@@ -2631,10 +2628,16 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                                                                 vma, address);
         }
 
-        if (!pagecache_page) {
-                page = pte_page(entry);
+        /*
+         * hugetlb_cow() requires page locks of pte_page(entry) and
+         * pagecache_page, so here we need take the former one
+         * when page != pagecache_page or !pagecache_page.
+         * Note that locking order is always pagecache_page -> page,
+         * so no worry about deadlock.
+         */
+        page = pte_page(entry);
+        if (page != pagecache_page)
                 lock_page(page);
-        }
 
         spin_lock(&mm->page_table_lock);
         /* Check for a racing update before calling hugetlb_cow */
@@ -2661,9 +2664,8 @@ out_page_table_lock:
         if (pagecache_page) {
                 unlock_page(pagecache_page);
                 put_page(pagecache_page);
-        } else {
-                unlock_page(page);
         }
+        unlock_page(page);
 
 out_mutex:
         mutex_unlock(&hugetlb_instantiation_mutex);
diff --git a/mm/rmap.c b/mm/rmap.c
index f6f0d2dda2ea..9d2ba01bd4f9 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1564,13 +1564,14 @@ static void __hugepage_set_anon_rmap(struct page *page,
         struct vm_area_struct *vma, unsigned long address, int exclusive)
 {
         struct anon_vma *anon_vma = vma->anon_vma;
+
         BUG_ON(!anon_vma);
-        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;
-        }
+
+        if (PageAnon(page))
+                return;
+        if (!exclusive)
+                anon_vma = anon_vma->root;
+
         anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
         page->mapping = (struct address_space *) anon_vma;
         page->index = linear_page_index(vma, address);
@@ -1581,6 +1582,8 @@ void hugepage_add_anon_rmap(struct page *page,
 {
         struct anon_vma *anon_vma = vma->anon_vma;
         int first;
+
+        BUG_ON(!PageLocked(page));
         BUG_ON(!anon_vma);
         BUG_ON(address < vma->vm_start || address >= vma->vm_end);
         first = atomic_inc_and_test(&page->_mapcount);