Merged revisions 73769 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

................
r73769 | russell | 2007-07-06 18:02:58 -0500 (Fri, 06 Jul 2007) | 12 lines

Merged revisions 73768 via svnmerge from 
https://origsvn.digium.com/svn/asterisk/branches/1.2

........
r73768 | russell | 2007-07-06 18:01:22 -0500 (Fri, 06 Jul 2007) | 4 lines

If a sip_pvt struct has already registered an extension state callback,
remove the old one before adding a new one.  If this isn't done, Asterisk
will crash.  (issue #10120)

........

................


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@73771 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -15400,8 +15400,11 @@ static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req,
 	}
 
 	/* Add subscription for extension state from the PBX core */
-	if (p->subscribed != MWI_NOTIFICATION && !resubscribe)
+	if (p->subscribed != MWI_NOTIFICATION && !resubscribe) {
+		if (p->stateid > -1)
+			ast_extension_state_del(p->stateid, cb_extensionstate);
 		p->stateid = ast_extension_state_add(p->context, p->exten, cb_extensionstate, p);
+	}
 
 	if (!ast_test_flag(req, SIP_PKT_IGNORE) && p)
 		p->lastinvite = seqno;