[PATCH] mempolicy: check home_node is in the nodes of policy

[Chunsheng Luo]

set_mempolicy_home_node should be used after setting the memory
policy. If the home_node isn't in the nodes of policy, we should
return failure to avoid misunderstanding.

Signed-off-by: Chunsheng Luo <luochunsheng@xxxxxxxx>
---
 mm/mempolicy.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 10a590ee1c89..9282be2ae18e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1536,6 +1536,12 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
 			err = -EOPNOTSUPP;
 			break;
 		}
+
+		if (!node_isset(home_node, old->nodes)) {
+			err = -EINVAL;
+			break;
+		}
+
 		new = mpol_dup(old);
 		if (IS_ERR(new)) {
 			err = PTR_ERR(new);
-- 
2.43.0