Fix handling of when a pvt disappears. Properly return the pvt locked

and don't hold the pvt lock while destroying the ast_channel.

(closes issue #13014)
Reported by: jpgrayson
Patches:
      chan_iax2_ast_iax2_new2.patch uploaded by jpgrayson (license 492)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@128795 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_iax2.c

@@ -3766,11 +3766,13 @@ static struct ast_channel *ast_iax2_new(int callno, int state, int capability)
 	ast_mutex_unlock(&iaxsl[callno]);
 	tmp = ast_channel_alloc(1, state, i->cid_num, i->cid_name, i->accountcode, i->exten, i->context, i->amaflags, "IAX2/%s-%d", i->host, i->callno);
 	ast_mutex_lock(&iaxsl[callno]);
-	if (!iaxs[callno]) {
+	if (i != iaxs[callno]) {
 		if (tmp) {
+			/* unlock and relock iaxsl[callno] to preserve locking order */
+			ast_mutex_unlock(&iaxsl[callno]);
 			ast_channel_free(tmp);
+			ast_mutex_lock(&iaxsl[callno]);
 		}
-		ast_mutex_unlock(&iaxsl[callno]);
 		return NULL;
 	}