---

yaml
---
r: 94032
b: refs/heads/master
c: f4e53d9
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 846a16bf0fc80dc95a414ffce465e3cbf9680247
+refs/heads/master: f4e53d910b7dde2685b177f1e7c3e3e0b4a42f7b

trunk/mm/mempolicy.c

@@ -591,16 +591,29 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags,
 			     nodemask_t *nodes)
 {
 	struct mempolicy *new;
+	struct mm_struct *mm = current->mm;
 
 	new = mpol_new(mode, flags, nodes);
 	if (IS_ERR(new))
 		return PTR_ERR(new);
+
+	/*
+	 * prevent changing our mempolicy while show_numa_maps()
+	 * is using it.
+	 * Note:  do_set_mempolicy() can be called at init time
+	 * with no 'mm'.
+	 */
+	if (mm)
+		down_write(&mm->mmap_sem);
 	mpol_put(current->mempolicy);
 	current->mempolicy = new;
 	mpol_set_task_struct_flag();
 	if (new && new->policy == MPOL_INTERLEAVE &&
 	    nodes_weight(new->v.nodes))
 		current->il_next = first_node(new->v.nodes);
+	if (mm)
+		up_write(&mm->mmap_sem);
+
 	return 0;
 }