Always ensure that the channel's tech_pvt reference is NULL after calling the

destroy callback.
(closes issue #13060)
Reported by: jpgrayson
Patches:
      chan_iax2_tech_pvt_crash.patch uploaded by jpgrayson (license 492)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@131421 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_iax2.c

@@ -3431,6 +3431,12 @@ static int iax2_hangup(struct ast_channel *c)
 				ast_log(LOG_DEBUG, "Really destroying %s now...\n", c->name);
 			iax2_destroy(callno);
 		}
+	} else if (c->tech_pvt) {
+		/* If this call no longer exists, but the channel still
+		 * references it we need to set the channel's tech_pvt to null
+		 * to avoid ast_channel_free() trying to free it.
+		 */
+		c->tech_pvt = NULL;
 	}
 	ast_mutex_unlock(&iaxsl[callno]);
 	if (option_verbose > 2)