Recently started seeing this error on few of the RAC environments.
ORA–00600: internal error code, arguments:[ORA-600[KCLANTILOCK_17]
After upgrade to 12.2, Due to this Instance got crashed.
As per metalink this is a known Bug 27162390
Patch 27162390: LNX64-181-RAC: LMS HIT ORA-600[KCLANTILOCK_17], INST CRASH
I’ve seen this in 12.2. As per Oracle it’s fixed in version 18.1