A friend of the database encountered this error message and the instance crash, find me to help diagnose the cause,
They have been enabled block change tracking to can take Inceremental backup. the db env was oracle EE 10.2.0.4 RAC on AIX.
# DB alert log
Errors in file /oraclelog/anbob/bdump/anbob1_ctwr_5309058.trc: ORA-00600: internal error code, arguments: [krccaub_2], , , , , , ,  Sat Feb 25 05:14:30 2017 Trace dumping is performing id=[cdmp_20170225051430] Sat Feb 25 05:14:31 2017 Errors in file /oraclelog/anbob/bdump/anbob1_ctwr_5309058.trc: ORA-00600: internal error code, arguments: [krccaub_2], , , , , , ,  Sat Feb 25 05:14:31 2017 CTWR: terminating instance due to error 487 --------->
# Trace FILE
ORACLE_HOME = /oracle/product/10204/db_1 System name: AIX Node name: actdb1 Release: 1 Version: 6 Machine: 00F8E0C64C00 Instance name: anbob1 Redo thread mounted by this instance: 1 Oracle process number: 53 Unix process pid: 5309058, image: oracle@actdb1 (CTWR) *** SERVICE NAME:(SYS$BACKGROUND) 2017-02-25 05:14:29.832 *** SESSION ID:(3784.1) 2017-02-25 05:14:29.832 *** 2017-02-25 05:14:29.832 ksedmp: internal or fatal error ORA-00600: internal error code, arguments: [krccaub_2], , , , , , ,  ----- Call Stack Trace ----- ------------------------- ksedst+001c ksedmp+0290 ksfdmp+0018 kgerinv+00dc kgeasnmierr+004c krccaub+00e4 krcchg+0298 krcptmo+02d0 ksbabs+03a8 ksbabs+03a8 krcpabs+0238 ksbrdp+04b4 opirip+03fc opidrv+0458 sou2o+0090 opimai_real+0150 main+0098
========== Diag ========
When data blocks change, shadow processes track the changed blocks in a private area of memory at the same time they generate redo.
When a commit is issued, the BCT information is copied to a shared area in Large Pool called ‘CTWR dba buffer’.
At the checkpoint, a new background process, Change Tracking Writer (CTWR), writes the information from the buffer to the change-tracking file.
CTWR =====>Block Change Tracking Writer or Checkpointer process (CTWR)
krccaub ===> [K]ernel [R]ecovery block [C]hange tracking [C]ache manager – [A]pply one [u]pdate to the [b]uffer
ORA-600 [krccaub_2] [a] [b]
When trying to apply one update to a buffer it is found that the locator is not for the correct file.
Arg [a] Absolute File number of the update to apply
Arg [b] Absolute File number of the buffer applying to
To disable block change tracking:
1. Start SQL*Plus and connect to a target database with administrator privileges.
2. Ensure that the target database is mounted or open.
3. Disable block change tracking.
Execute the following ALTER DATABASE statement:
ALTER DATABASE DISABLE BLOCK CHANGE TRACKING;
One-off patch 6666248
upgrade 126.96.36.199 or above