HI,
ORA-01041: internal error. hostdef extension doesn't exist
For the issue you could restart the system to release allocated shared memory.
ORA-03113: end-of-file on communication channel
There is no update in alert log and well as user trace.
For this error code i would check for space on system first,there should not be stuck situations on the device.If possible share the space availability on the system first.
Second which you need to check for correct permissions & ownerships on the Database files.
Regards,