Fix the actual place that was pointed out, for previous commit.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@270983 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_agent.c

@@ -2298,7 +2298,9 @@ static int function_agent(struct ast_channel *chan, const char *cmd, char *data,
 		} 
 	} else if (!strcasecmp(args.item, "fullchannel")) {
 		if (agent->chan) {
+			ast_channel_lock(agent->chan);
 			ast_copy_string(buf, agent->chan->name, len);
+			ast_channel_unlock(agent->chan);
 		} 
 	} else if (!strcasecmp(args.item, "exten")) {
 		buf[0] = '\0';