DB2 FOR LUW / DB2FORLUW / B10 - DB2

Possible deadlatch in sqloMemInit() when it loads client-side
library to execute trusted routine as shown in the following
stack trace:

Thread 197 (Thread 0x7f47473fe700 (LWP 21766)):
#0  0x00007f4b8b84d53d in nanosleep () from
/usr/lib64/libpthread.so.0
#1  0x00007f4b7f262efc in ossLockGetConflict () from
/home/appusers/db2m7r/sqllib/lib64/libdb2osse.so.1
#2  0x00007f47057fbf3d in sqloMemInit() () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#3  0x00007f47057fbe9f in sqloGetMemSet () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#4  0x00007f470579d672 in sqloopenp () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#5  0x00007f4705621fd8 in openLogFile(char*, PD_LOGFILE_HANDLE*,
long*, int*, unsigned int*, char*, unsigned long,
#6  0x00007f4705629084 in PDLogFacility::open
#7  0x00007f470561c376 in pdLogInternal
#8  0x00007f470561b67b in pdLog () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#9  0x00007f470633db40 in sqloGetEnvInternal () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#10 0x00007f470580d72c in sqlo_refresh_env () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#11 0x00007f470580e933 in sqloInstanceLocalDataPath () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#12 0x00007f470580e6d9 in sqloGetConfigPath () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#13 0x00007f470581f8b6 in EnvKeyName(char*, int, char const*,
int)
#14 0x00007f470581fdb3 in EnvPrfOpen(char const*, int,
SEnvProfile**)
#15 0x00007f470581ad39 in EnvRegGetProfile(SEnvRegistry*, char
const*, int, SEnvProfile**)
#16 0x00007f470633d6e2 in sqloGetEnvInternal () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#17 0x00007f47057f3722 in md_Initialize() () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#18 0x00007f47057fc14f in sqloimem() () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#19 0x00007f47057fbf1b in sqloMemInit() () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#20 0x00007f47057fd163 in sqlogmshr () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#21 0x00007f47057fcf0f in sqloGetPrivateSet () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#22 0x00007f47057fce8f in MemOssPool(SQLO_MEM_POOL**) () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#23 0x00007f47057f8ef0 in sqlogmblkEx () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#24 0x00007f47056c6e66 in
sqleBeginTrustedCtxInternal(sql_app_ctx**, sql_static_data*)
#25 0x00007f47056ffa25 in sqleUCtrustedRtnInit () from
/home/appusers/db2m7r/sqllib/lib64/libdb2.so.1
#26 0x00007f4b82b92654 in sqleUCtrustedLvlInit(sql_static_data*,
sqlrr_cb*, sqlri_ufob*)
#27 0x00007f4b83d2612c in sqlriOneTimeInitRtn1Trusted(sqlrr_cb*,
sqlri_ufob*, bool)
#28 0x00007f4b83d24c63 in sqlriOneTimeInitRtn(sqlrr_cb*,
sqlri_ufob*, bool)
#29 0x00007f4b86a14466 in sqlriusf_common(sqlrr_cb*,
sqlri_ufob*) () from
/home/appusers/db2m7r/sqllib/lib64/libdb2e.so.1
#30 0x00007f4b8600c294 in sqlriusf(sqlrr_cb*) () from
/home/appusers/db2m7r/sqllib/lib64/libdb2e.so.1
#31 0x00007f4b86a05df6 in sqlriSectInvoke(sqlrr_cb*,
sqlri_opparm*)
#32 0x00007f4b869e8f8a in
sqlrr_process_execute_request(sqlrr_cb*, int, bool)
#33 0x00007f4b869e635c in sqlrr_execute(db2UCinterface*,
UCstpInfo*)
#34 0x00007f4b86929936 in sqljs_ddm_excsqlstt(db2UCinterface*,
sqljDDMObject*)
#35 0x00007f4b86928ece in sqljsParseRdbAccessed(sqljsDrdaAsCb*,
sqljDDMObject*, db2UCinterface*)
#36 0x00007f4b82c5a1ec in sqljsParse(sqljsDrdaAsCb*,
db2UCinterface*, sqeAgent*, bool)
#37 0x00007f4b82c54779 in sqljsSqlam(db2UCinterface*, sqeAgent*,
bool)
#38 0x00007f4b82c52c8c in sqljsDriveRequests(sqeAgent*,
db2UCconHandle*)
#39 0x00007f4b82c4fce9 in
sqljsDrdaAsInnerDriver(SQLCC_INITSTRUCT_T*, bool)
#40 0x00007f4b82c4f8db in sqljsDrdaAsDriver(SQLCC_INITSTRUCT_T*)
() from /home/appusers/db2m7r/sqllib/lib64/libdb2e.so.1
#41 0x00007f4b82949a4f in sqeAgent::RunEDU() () from
/home/appusers/db2m7r/sqllib/lib64/libdb2e.so.1
#42 0x00007f4b84188eb7 in sqzEDUObj::EDUDriver() () from
/home/appusers/db2m7r/sqllib/lib64/libdb2e.so.1
#43 0x00007f4b8392fb93 in sqloEDUEntry () from
/home/appusers/db2m7r/sqllib/lib64/libdb2e.so.1
#44 0x00007f4b8b84574a in start_thread () from
/usr/lib64/libpthread.so.0
#45 0x00007f4b7e4d9f6d in clone () from /usr/lib64/libc.so.6

The problem has only been observed in an environment were there
had been issues accessing the db2 global registry
(/var/db2/global.reg). I.e. it is unlikely to happen in a
"healthy" environment.

****************************************************************
* USERS AFFECTED:                                              *
* ALL                                                          *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade to Db2 Version 11.1 Mod 4 Fix Pack 6.                *
****************************************************************

Try to keep a "dummy" trusted routine opened in the instance, so
the client side library will always be loaded in db2 (and never
unloaded). For example have a db2 connection and issue something
like this :

   db2 values dayofweek(current timestamp)

and never let that go / keep it open for the lifetime of the
database / instance (just need it for one database).

not known / see Local fix

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

02.06.2020
16.03.2021
16.03.2021