I just got some detailed error message from SQL logs. There is no way to manually issue a check point as the transaction log is 106% full. I can't do any backup as backup need some space in transaction log too.

2011-02-04 04:57:29.77 spid5s Starting up database 'msdb'.

2011-02-04 04:57:30.17 spid5s 5 transactions rolled forward in database 'msdb' (4). This is an informational message only. No user action is required.

2011-02-04 04:57:30.20 spid5s 0 transactions rolled back in database 'msdb' (4). This is an informational message only. No user action is required.

2011-02-04 04:57:30.20 spid5s Recovery is writing a checkpoint in database 'msdb' (4). This is an informational message only. No user action is required.

2011-02-04 04:57:34.32 spid5s Error: 9002, Severity: 17, State: 1.

2011-02-04 04:57:34.32 spid5s The transaction log for database 'msdb' is full. To find out why space in the log cannot be reused, see the log_reuse_wait_desc column in sys.databases

2011-02-04 04:57:34.32 spid5s Could not write a checkpoint record in database ID 4 because the log is out of space. Contact the database administrator to truncate the log or allocate more space to the database log files.

2011-02-04 04:57:34.37 spid5s Recovery is complete. This is an informational message only. No user action is required.