db2数据库近一年运行正常，9月4日晚突然连不上数据库，报密码错误，重启数据库后正常？

1. 系统环境：aix7+db2 10.5
2. 上层应用报错，因密码校验错误，无法连接数据库；但是在报错的前一刻，数据库连接还是正常的，数据入库也正常。
   [INFO] 2018-09-04 11:01:11,169 MI-03 File "AWOS201809041100.YMD" process finished!
   [ERROR] 2018-09-04 11:01:11,180 ME-04 DB connect error!
   Can't establish the database connection!
   com.ibm.db2.jcc.am.SqlInvalidAuthorizationSpecException: jcc2013[4.16.53] Connection authorization failure
   occurred. Reason: User ID or Password invalid. ERRORCODE=-4214, SQLSTATE=28000. This is 1 try.
   Please connect with the DBA and confirm the database and listener is open !
   [INFO] 2018-09-04 11:01:21,235 MI-03 File "AWOS201809041101.UUU" process finished!

[INFO] 2018-09-04 11:22:11,053 MI-03 File "AWOS201809041122.SPD" process finished!
[ERROR] 2018-09-04 11:22:11,064 ME-04 DB connect error!
Can't establish the database connection!
com.ibm.db2.jcc.am.SqlInvalidAuthorizationSpecException: jcc2013[4.16.53] Connection authorization failure
occurred. Reason: User ID or Password invalid. ERRORCODE=-4214, SQLSTATE=28000. This is 1 try.
Please connect with the DBA and confirm the database and listener is open !
[INFO] 2018-09-04 11:22:21,101 MI-03 File "AWOS201809041122.SSS" process finished!
[ERROR] 2018-09-04 11:22:26,103 ME-04 DB connect error!
Can't establish the database connection!
com.ibm.db2.jcc.am.DisconnectNonTransientConnectionException: jcc2030[4.16.53] A communication error occur
red during operations on the connection's underlying socket, socket input stream,
or socket output stream. Error location: Reply.fill() - socketInputStream.read (-1). Message: Read timed out. ERRORCODE
=-4499, SQLSTATE=08001. This is 1 try.
Please connect with the DBA and confirm the database and listener is open !
[INFO] 2018-09-04 11:22:36,137 MI-03 File "AWOS201809041122.SWZ" process finished!

[INFO] 2018-09-04 11:25:03,889 MI-03 File "AWOS201809041125.GGG" process finished!
[ERROR] 2018-09-04 11:25:12,937 ME-04 DB connect error!
Can't establish the database connection!
com.ibm.db2.jcc.am.SqlInvalidAuthorizationSpecException: jcc2013[4.16.53] Connection authorization failure
occurred. Reason: User ID or Password invalid. ERRORCODE=-4214, SQLSTATE=28000. This is 1 try.
Please connect with the DBA and confirm the database and listener is open !
[ERROR] 2018-09-04 11:25:27,939 ME-04 DB connect error!
Can't establish the database connection!
com.ibm.db2.jcc.am.DisconnectNonTransientConnectionException: jcc2030[4.16.53] A communication error occur
red during operations on the connection's underlying socket, socket input stream,
or socket output stream. Error location: Reply.fill() - socketInputStream.read (-1). Message: Read timed out. ERRORCODE
=-4499, SQLSTATE=08001. This is 2 try.

2. 操作系统未对用户设置密码过期
   
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   但是从图片也看出来，当时显示最后一次“未能成功登陆的时间”是201809041125...，这个时间与应用当时报错的时间基本一致。
3. db2diag的报错信息
   db2inst1@ZBBB_DB01 $ db2diag -t 2018-09-04-11 db2diag.log|more
   2018-09-04-11.01.11.179444+000 I3301372A464 LEVEL: Warning
   PID : 7340068 TID : 39438 PROC : db2sysc 0
   INSTANCE: db2inst1 NODE : 000 DB : ZBBB
   APPHDL : 0-55481
   HOSTNAME: ZBBB_DB01
   EDUID : 39438 EDUNAME: db2agent (ZBBB) 0
   FUNCTION: DB2 UDB, bsu security, sqlexLogPluginMessage, probe:20
   DATA #1 : String with size, 66 bytes
   Password validation for user userdbs failed with rc = -2146500507

2018-09-04-11.01.11.179771+000 I3301837A462 LEVEL: Warning
PID : 7340068 TID : 39438 PROC : db2sysc 0
INSTANCE: db2inst1 NODE : 000 DB : ZBBB
APPHDL : 0-55481
HOSTNAME: ZBBB_DB01
EDUID : 39438 EDUNAME: db2agent (ZBBB) 0
FUNCTION: DB2 UDB, bsu security, sqlexSlsSystemAuthenticate, probe:150
MESSAGE : application id:
DATA #1 : String with size, 30 bytes
172.19.2.26.56078.181009072619

2018-09-04-11.22.11.063525+000 I3302300A464 LEVEL: Warning
PID : 7340068 TID : 52900 PROC : db2sysc 0
INSTANCE: db2inst1 NODE : 000 DB : ZBBB
APPHDL : 0-57656
HOSTNAME: ZBBB_DB01
EDUID : 52900 EDUNAME: db2agent (ZBBB) 0
FUNCTION: DB2 UDB, bsu security, sqlexLogPluginMessage, probe:20
DATA #1 : String with size, 66 bytes
Password validation for user userdbs failed with rc = -2146500507

2018-09-04-11.22.11.063843+000 I3302765A462 LEVEL: Warning
PID : 7340068 TID : 52900 PROC : db2sysc 0
INSTANCE: db2inst1 NODE : 000 DB : ZBBB
APPHDL : 0-57656
HOSTNAME: ZBBB_DB01
EDUID : 52900 EDUNAME: db2agent (ZBBB) 0
FUNCTION: DB2 UDB, bsu security, sqlexSlsSystemAuthenticate, probe:150
MESSAGE : application id:
DATA #1 : String with size, 30 bytes
172.19.2.26.59126.181009081907

2018-09-04-11.25.12.936559+000 I3303228A464 LEVEL: Warning
PID : 7340068 TID : 30293 PROC : db2sysc 0
INSTANCE: db2inst1 NODE : 000 DB : ZBBB
APPHDL : 0-59597
HOSTNAME: ZBBB_DB01
EDUID : 30293 EDUNAME: db2agent (ZBBB) 0
FUNCTION: DB2 UDB, bsu security, sqlexLogPluginMessage, probe:20
DATA #1 : String with size, 66 bytes
Password validation for user userdbs failed with rc = -2146500507

2018-09-04-11.25.12.936881+000 I3303693A462 LEVEL: Warning
PID : 7340068 TID : 30293 PROC : db2sysc 0
INSTANCE: db2inst1 NODE : 000 DB : ZBBB
APPHDL : 0-59597
HOSTNAME: ZBBB_DB01
EDUID : 30293 EDUNAME: db2agent (ZBBB) 0
FUNCTION: DB2 UDB, bsu security, sqlexSlsSystemAuthenticate, probe:150
MESSAGE : application id:
DATA #1 : String with size, 30 bytes
172.19.2.26.59533.181009082613

2018-09-04-11.49.41.040527+000 E3304156A580 LEVEL: Info
PID : 7340068 TID : 19792 PROC : db2sysc 0
INSTANCE: db2inst1 NODE : 000 DB : ZBBB
APPHDL : 0-7991 APPID: 172.19.2.26.65172.180816084656
AUTHID : USERDBS HOSTNAME: ZBBB_DB01
EDUID : 19792 EDUNAME: db2agent (ZBBB) 0
FUNCTION: DB2 UDB, buffer pool services, sqlbCleanupBeforeTerm, probe:7834
DATA #1 : SQLP_LSN8, PD_TYPE_SQLP_LSN8, 8 bytes
00000000F64523BE
DATA #2 : SQLP_LSN8, PD_TYPE_SQLP_LSN8, 8 bytes
00000000F64523BE

2018-09-04-11.54.14.941905+000 I3304737A457 LEVEL: Warning
PID : 7340068 TID : 2057 PROC : db2sysc 0
INSTANCE: db2inst1 NODE : 000
HOSTNAME: ZBBB_DB01
EDUID : 2057 EDUNAME: db2tcpcm 0
FUNCTION: DB2 UDB, fast comm manager, sqkfDynamicResourceMgr::AdjustResources, probe:175
MESSAGE : FCM Automatic/Dynamic Resource Adjustment (Session): 128 successfully

      allocated. New total is 384

2018-09-04-12.03.28.154743+000 I3305195A397 LEVEL: Event
PID : 13697042 TID : 1 PROC : db2stop
INSTANCE: db2inst1 NODE : 000
HOSTNAME: ZBBB_DB01
EDUID : 1
FUNCTION: DB2 UDB, base sys utilities, sqleGetStStLockFile, probe:14311
MESSAGE : Obtained exclusive mode lock on the file:
DATA #1 : String, 39 bytes
/home/db2inst1/sqllib/ctrl/db2strst.lck
Standard input

4. 操作系统当时的errpt报错，报错的3个时间点与应用基本也一致，同时db2sysc生成了core文件，因系统为生产环境，且不知如何再现该故障， 不知如何查看这个core文件内容。使用more查看core文件内容，多为乱码，似乎是与密码相关的故障。
   mhdb2@ZBBB_DB01 $ db2 connect to zbbb user userdbs using userdbs

   Database Connection Information

   Database server = DB2/AIX64 10.5.2
   SQL authorization ID = USERDBS
   Local database alias = ZBBB

mhdb2@ZBBB_DB01 $ db2 terminate
DB20000I The TERMINATE command completed successfully.
mhdb2@ZBBB_DB01 $ errpt
IDENTIFIER TIMESTAMP T C RESOURCE_NAME DESCRIPTION
A924A5FC 0904112518 P S SYSPROC SOFTWARE PROGRAM ABNORMALLY TERMINATED
A924A5FC 0904112218 P S SYSPROC SOFTWARE PROGRAM ABNORMALLY TERMINATED
A924A5FC 0904110118 P S SYSPROC SOFTWARE PROGRAM ABNORMALLY TERMINATED

mhdb2@ZBBB_DB01 $ errpt -aj A924A5FC|more

LABEL: CORE_DUMP
IDENTIFIER: A924A5FC

Date/Time: Tue Sep 4 11:25:23 CUT 2018
Sequence Number: 140
Machine Id: 00FA067B4C00
Node Id: ZBBB_DB01
Class: S
Type: PERM
WPAR: Global
Resource Name: SYSPROC

Description
SOFTWARE PROGRAM ABNORMALLY TERMINATED

Probable Causes
SOFTWARE PROGRAM

User Causes
USER GENERATED SIGNAL

    Recommended Actions
    CORRECT THEN RETRY

Failure Causes
SOFTWARE PROGRAM

    Recommended Actions
    RERUN THE APPLICATION PROGRAM
    IF PROBLEM PERSISTS THEN DO THE FOLLOWING

Standard input

请各位大侠帮忙看看。重启数据库后就又能正常连接数据库了，用的密码依然是旧密码。