Since a sip request's data field is now a stringfield, we not only have to check

if the string is zero-length, but also if the data field is non-null.

(closes issue #12250)
Reported by: caio1982



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@109681 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -4763,7 +4763,7 @@ static int sip_hangup(struct ast_channel *ast)
 		sip_scheddestroy(p, DEFAULT_TRANS_TIMEOUT);
 	/* Start the process if it's not already started */
-	if (!p->alreadygone && !ast_strlen_zero(p->initreq.data->str)) {
+	if (!p->alreadygone && p->initreq.data && !ast_strlen_zero(p->initreq.data->str)) {
 		if (needcancel) {	/* Outgoing call, not up */
 			if (ast_test_flag(&p->flags[0], SIP_OUTGOING)) {
 				/* stop retransmitting an INVITE that has not received a response */