DB Design :: Log File Corrupted While Making Database Readonly

We have database when trying to make read only throwing below error: with stack dump

Location:              recovery.cpp:4517
Expression:         m_recoveryUnit->IsIntendedUpdateable ()
SPID:                     51
Process ID:          6448
Msg 926, Level 14, State 1, Line 1
Database 'XXXX' cannot be opened. It has been marked SUSPECT by recovery.

See the SQL Server errorlog for more information.
Msg 5069, Level 16, State 1, Line 1
ALTER DATABASE statement failed.
Msg 3624, Level 20, State 1, Line 1

A system assertion check has failed. Check the SQL Server error log for details. Typically, an assertion failure is caused by a software bug or data corruption. To check for database corruption, consider running DBCC CHECKDB. If you agreed to send dumps to Microsoft during setup, a mini dump will be sent to Microsoft. An update might be available from Microsoft in the latest Service Pack or in a QFE from Technical Support.

Msg 3313, Level 21, State 2, Line 1

During redoing of a logged operation in database 'XXXX', an error occurred at log record ID (0:0:0). Typically, the specific failure is previously logged as an error in the Windows Event Log service. Restore the database from a full backup, or repair the database.

Msg 3414, Level 21, State 1, Line 1

An error occurred during recovery, preventing the database 'XXXX' (database ID 7) from restarting. Diagnose the recovery errors and fix them, or restore from a known good backup. If errors are not corrected or expected, contact Technical Support.

Investigation DONE:

- DBcc checkdb shown Clean 
- database is online and able to access
-Detached database and attached with rebuild log, still could not bring database read_only

SQL version : SQL server 2008 SP4.