1 files changed, 20 insertions, 5 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index b3f00b616b81..84b12624ceb0 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3184,10 +3184,16 @@ static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
  * mapping->flags avoid to take the same lock twice, if more than one
  * vma in this mm is backed by the same anon_vma or address_space.
  *
- * We can take all the locks in random order because the VM code
- * taking i_mmap_rwsem or anon_vma->rwsem outside the mmap_sem never
- * takes more than one of them in a row. Secondly we're protected
- * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex.
+ * We take locks in following order, accordingly to comment at beginning
+ * of mm/rmap.c:
+ *   - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for
+ *     hugetlb mapping);
+ *   - all i_mmap_rwsem locks;
+ *   - all anon_vma->rwseml
+ *
+ * We can take all locks within these types randomly because the VM code
+ * doesn't nest them and we protected from parallel mm_take_all_locks() by
+ * mm_all_locks_mutex.
  *
  * mm_take_all_locks() and mm_drop_all_locks are expensive operations
  * that may have to take thousand of locks.
@@ -3206,7 +3212,16 @@ int mm_take_all_locks(struct mm_struct *mm)
         for (vma = mm->mmap; vma; vma = vma->vm_next) {
                 if (signal_pending(current))
                         goto out_unlock;
-                if (vma->vm_file && vma->vm_file->f_mapping)
+                if (vma->vm_file && vma->vm_file->f_mapping &&
+                                is_vm_hugetlb_page(vma))
+                        vm_lock_mapping(mm, vma->vm_file->f_mapping);
+        }
+
+        for (vma = mm->mmap; vma; vma = vma->vm_next) {
+                if (signal_pending(current))
+                        goto out_unlock;
+                if (vma->vm_file && vma->vm_file->f_mapping &&
+                                !is_vm_hugetlb_page(vma))
                         vm_lock_mapping(mm, vma->vm_file->f_mapping);
         }