We should only unsubscribe to the device state event

subscription if we have previously subscribed. Otherwise
a segfault will occur.

(closes issue #13476)
Reported by: jonnt
Patches:
      13476.patch uploaded by putnopvut (license 60)
Tested by: jonnt

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@143609 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_agent.c b/channels/chan_agent.c
index 83dbd38..f84c0f0 100644 (file)
--- a/channels/chan_agent.c
+++ b/channels/chan_agent.c
@@ -2535,7 +2535,9 @@ static int unload_module(void)
        /* First, take us out of the channel loop */
        ast_channel_unregister(&agent_tech);
        /* Delete devicestate subscription */
-       agent_devicestate_sub = ast_event_unsubscribe(agent_devicestate_sub);
+       if (agent_devicestate_sub) {
+               agent_devicestate_sub = ast_event_unsubscribe(agent_devicestate_sub);
+       }
        /* Unregister dialplan functions */
        ast_custom_function_unregister(&agent_function);        
        /* Unregister CLI commands */