ORA-600 errors are raised from the kernel code of the Oracle RDBMS software when an internal inconsistency is detected or an unexpected condition is met. This situation is not necessarily a bug as it might be caused by problems with the Operating System, lack of resources, hardware failures, etc.
With the ORA-600 error comes a list of arguments in square brackets. The first of these arguments tells us from where in the code the error was caught and thus is the key information in identifying the problem. This argument is either a number or a character string. The remaining arguments are used to supply further information (e.g. values of internal variables etc).
Whenever an ORA-600 error is raised a trace file is generated and an entry written to the alert.log with details of the trace file location. Starting with Oracle Database 11g Release 1, the diagnosability infrastructure was introduced which places the trace and core files into a location controlled by the DIAGNOSTIC_DEST initialization parameter when an incident, such as an ORA-600 is created. For earlier versions, the trace file will be written to either USER_DUMP_DEST (if the error was caught in a user process) or BACKGROUND_DUMP_DEST (if the error was caught in a background process like PMON or SMON). The trace file contains vital information about what led to the error condition.