check if vnn is a valid pointer before dereferencing it

based on rustys patch for bz62783

diff --git a/server/ctdb_takeover.c b/server/ctdb_takeover.c
index b18c030092147219dfe66f0f3c4177009c521a86..e80e30328145a91275aad32254745329876d29ad 100644 (file)
--- a/server/ctdb_takeover.c
+++ b/server/ctdb_takeover.c
@@ -2300,7 +2300,9 @@ static void ctdb_tickle_sentenced_connections(struct event_context *ev, struct t
  */
 static int ctdb_killtcp_destructor(struct ctdb_kill_tcp *killtcp)
 {
-       killtcp->vnn->killtcp = NULL;
+       if (killtcp->vnn) {
+               killtcp->vnn->killtcp = NULL;
+       }
        return 0;
 }