abort when cnt is too high

git-svn-id: svn://localhost/ardour2/branches/3.0@9619 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/ardour/audioregion.cc

@@ -390,6 +390,10 @@ AudioRegion::_read_at (const SourceList& /*srcs*/, framecnt_t limit,
 	     << " chan " << chan_n
 	     << " rops " << hex << rops << dec
 	     << endl;
+	
+	if (cnt > 64 * 1024) {
+		abort ();
+	}
 
 	if (n_channels() == 0) {
 		return 0;