Customer report system when into read-only mode and they was required to restart the system. From the logs, looks like ProcMon on pm1 restarted which initated a re-initialzation of DDL/DMLProc. Rollback failed causing the system to go into read-only mode.

Jan 4 23:56:15 ip-10-85-150-66 ProcessManager[27605]: 15.647488 |0|0|0| D 17 CAL0000: reinitProcessType: ReInit all DDLProc
Jan 4 23:56:15 ip-10-85-150-66 ProcessManager[27605]: 15.655802 |0|0|0| D 17 CAL0000: sendMsgProcMon: Process module um1
Jan 4 23:56:16 ip-10-85-150-66 ProcessManager[27605]: 16.647188 |0|0|0| D 17 CAL0000: DDLProc process is reinited by request.
Jan 4 23:56:16 ip-10-85-150-66 ProcessManager[27605]: 16.647277 |0|0|0| D 17 CAL0000: reinitProcessType: ACK received from Process-Monitor, return status = 0
Jan 4 23:56:16 ip-10-85-150-66 ProcessManager[27605]: 16.647429 |0|0|0| D 17 CAL0000: reinitProcessType: ReInit all DMLProc
Jan 4 23:56:16 ip-10-85-150-66 ProcessManager[27605]: 16.656973 |0|0|0| D 17 CAL0000: sendMsgProcMon: Process module um1
Jan 4 23:56:17 ip-10-85-150-66 ProcessMonitor[27415]: 17.228943 |0|0|0| D 18 CAL0000: statusControl: REQUEST RECEIVED: Set Process pm1/ProcessMonitor State = ACTIVE

Jan 4 23:56:12 ip-10-85-150-68 DMLProc[35138]: 12.973026 |0|0|0| C 20 CAL0002: problem with rollback transaction 116060and DBRM is setting to readonly and table lock is not released: lookupLocal from extent map error encountered while looking up lbid:verID 2199479296:0 and error code is -1 with message UNKNOWN (-1) (WriteEngine returns error 1)