IT31050: ON LINUX, DB2 MAY HANG AFTER ISSUING DB2PD -STACK ALL, DB2PD -DUMP ALL IN QUICK SUCCESSION

APAR status

• Closed as program error.

Error description

• On Linux, db2 may hang after issuing db2pd -stack all, db2pd
  -dump in quick succession. This is due to the second signal
  triggering a thread to interrupt the dumping of a stack trace
  ("stack" files) while still holding a mutex/lock related to the
  Linux dladdr api call.
  
  db2 trap files will appear incomplete, and issuing gstack on the
  db2sysc process will show many threads waiting in the dladdr
  call :
    gstack `db2pd -edus | awk '/db2sysc PID/ {print $3}'` >
  gstack.db2sysc
  
  #0  0x00007f8f3827454d in __lll_lock_wait () from
  /lib64/libpthread.so.0
  #1  0x00007f8f3826feb6 in _L_lock_941 () from
  /lib64/libpthread.so.0
  #2  0x00007f8f3826fdaf in pthread_mutex_lock () from
  /lib64/libpthread.so.0
  #3  0x00007f8f27d532d2 in _dl_addr () from /lib64/libc.so.6
  #4  0x00007f8f28d0c05d in ossTraceFunction(void*, OSSTrapFile&,
  char const*) () from
  /db2home/db2inst1/sqllib/lib64/libdb2osse.so.1
  #5  0x00007f8f28d0cebc in ossDumpStackTraceInternal(unsigned
  long, OSSTrapFile&, int, siginfo*, void*, unsigned long,
  unsigned long) () from
  /db2home/db2inst1/sqllib/lib64/libdb2osse.so.1
  #6  0x00007f8f28d0c95b in ossDumpStackTraceV98 () from
  /db2home/db2inst1/sqllib/lib64/libdb2osse.so.1
  #7  0x00007f8f28d08b47 in OSSTrapFile::dumpEx(unsigned long,
  int, siginfo*, void*, unsigned long) () from
  /db2home/db2inst1/sqllib/lib64/libdb2osse.so.1
  #8  0x00007f8f30570427 in sqlo_trce () from
  /db2home/db2inst1/sqllib/lib64/libdb2e.so.1
  #9  0x00007f8f306dbeab in sqloDumpDiagInfoHandler () from
  /db2home/db2inst1/sqllib/lib64/libdb2e.so.1
  #10 <signal handler called>
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * all                                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to 	db2_v111m4fp6 or higher                          *
  ****************************************************************
  

Problem conclusion

• Upgrade to 	db2_v111m4fp6 or higher
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels