I faced with that error on one of our 11.2.0.4 database.

We got ora-600 error on our alert.log. After investigate issue we have found our error is matches unpublished Bug 5368945 – ORA-00600: [KDSGRP1] ON XQUERY

A common situation hitting this bug is when using XDB/XML queries (XQUERY/SQLX) as IOT’s can be involved.

You may use Workaround to can create Alternate execution plans might avoid this problem.

Check also involved tables for corruption with following command:
SQL> ANALYZE TABLE . VALIDATE STRUCTURE CASCADE;

Reference:
Select Fails With ORA-600 [kdsgrp1] (Doc ID 1331499.1)
Causes and Solutions for ora-600 [kdsgrp1] (Doc ID 1332252.1)