From 82a7c93b47926d61f390f53bacd3ec9528362315 Mon Sep 17 00:00:00 2001
From: nvt <nvt@sics.se>
Date: Mon, 30 Jan 2012 23:51:07 +0100
Subject: [PATCH] Check return value.

---
 core/net/rpl/rpl-dag.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index 2ec8cab0a..6bea3d46d 100755
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -1193,7 +1193,9 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
       PRINTF("\n");
     } else {
       p = rpl_find_parent(previous_dag, from);
-      rpl_move_parent(previous_dag, dag, p);
+      if(p != NULL) {
+        rpl_move_parent(previous_dag, dag, p);
+      }
     }
   } else {
     if(p->rank == dio->rank) {