Today fought with error in alert log (Database 126.96.36.199.11 on Exadata, image 188.8.131.52.2):
ORA-00600: internal error code, arguments: [ossnet_assign_msgid_1], , , , , , , , , , 
ERROR: unrecoverable error ORA-600 raised in ASM I/O path
MOS found nothing direct links about this error.
As of note " 184.108.40.206 Bundle Patches for Engineered Systems and DB In-Memory - List of Fixes in each Bundle (Doc ID 1937782.1) "
this is the bug:
ORA-600 [OSSNET_ASSIGN_MSGID_1] CAUSED BY TO SMALL VALUE _SMM_AUTO_MIN_IO_SIZE
The solution which helped to us:
alter system set "_smm_auto_max_io_size"=2048 scope=both sid='*';
alter system set "_smm_auto_min_io_size"=2040 scope=both sid='*';