diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c
index bcbcf47506c9..2f0181b2566d 100644
--- a/net/ceph/mon_client.c
+++ b/net/ceph/mon_client.c
@@ -943,7 +943,7 @@ static void handle_command_ack(struct ceph_mon_client *monc,
 {
 	struct ceph_mon_generic_request *req;
 	void *p = msg->front.iov_base;
-	void *const end = p + msg->front_alloc_len;
+	void *const end = p + msg->front.iov_len;
 	u64 tid = le64_to_cpu(msg->hdr.tid);
 
 	dout("%s msg %p tid %llu\n", __func__, msg, tid);