Index: linux-2.6/kernel/fork.c
===================================================================
--- linux-2.6.orig/kernel/fork.c	2005-08-04 15:24:36.000000000 +1000
+++ linux-2.6/kernel/fork.c	2005-08-26 00:20:50.000000000 +1000
@@ -256,7 +256,6 @@ static inline int dup_mmap(struct mm_str
 		 * Note that, exceptionally, here the vma is inserted
 		 * without holding mm->mmap_sem.
 		 */
-		spin_lock(&mm->page_table_lock);
 		*pprev = tmp;
 		pprev = &tmp->vm_next;
 
@@ -265,8 +264,11 @@ static inline int dup_mmap(struct mm_str
 		rb_parent = &tmp->vm_rb;
 
 		mm->map_count++;
-		retval = copy_page_range(mm, current->mm, tmp);
-		spin_unlock(&mm->page_table_lock);
+		if (!(file && (tmp->vm_flags & VM_SHARED))) {
+			spin_lock(&mm->page_table_lock);
+			retval = copy_page_range(mm, current->mm, tmp);
+			spin_unlock(&mm->page_table_lock);
+		}
 
 		if (tmp->vm_ops && tmp->vm_ops->open)
 			tmp->vm_ops->open(tmp);