IT32877: SIGNAL STACK OVERFLOW WHILE EXECUTING IN THE SIGNAL HANDLE SQLOEDUCODETRAPHANDLER

APAR status

• Closed as program error.

Error description

• Default stack of 64 KB on Linux too small.
  
  At the time of the signal overflow, we ended up with the follow
  stack chain:
  
  #0  sqloGetMemoryBlockExtended
  #1  sqlogmblkWithResourceFileAndLine<void>
  #2  sqloOpenStreamFile
  #3  sqloOpenNodeList (pszCfgFilePath=0x0,
  #4  sqloDB2NodesCfgHandle::open
  #5  sqloReadDb2nodesWithHandleInternal
  #6  sqloReadDb2nodesInternal
  #7  pdGetDftNodeNum
  #9  pdStartFODC
  #10 qloEDUCodeTrapHandler (signum=11,
  
  
  The main issue here is that we exhausted the 64K signal stack
  and we ended with a truncated stack in the trap file:
  
  <POFDisassembly>
   _ZN14sqeWLDispDebug7EnterFnEjP15sql_static_data + 0x0029
  (/home/lpham/sqllib/lib64/libdb2e.so.1)
  
          0x00007FFFE357C741 : 0FB680900000000F
  </POFDisassembly>
  <StackTrace>
  -----FUNC-ADDR---- ------FUNCTION + OFFSET------
  0x00007FFFB80A344A
  _Z25ossDumpStackTraceInternalmR11OSSTrapFileiP7siginfoPvmm +
  0x04ea
                  (/home/lpham/sqllib/lib64/libdb2osse.so.1)
  0x00007FFFB80A3CB9 ossDumpStackTraceV98 + 0x007f
                  (/home/lpham/sqllib/lib64/libdb2osse.so.1)
  0x00007FFFB809E0AC _ZN11OSSTrapFile6dumpExEmiP7siginfoPvm +
  0x04e0
                  (/home/lpham/sqllib/lib64/libdb2osse.so.1)
  0x00007FFFE6EA0991 sqlo_trce + 0x06bb
                  (/home/lpham/sqllib/lib64/libdb2e.so.1)
  0x00007FFFE7183CAB sqloEDUCodeTrapHandler + 0x07e7
                  (/home/lpham/sqllib/lib64/libdb2e.so.1)
  0x00007FFFF7BCF850 address: 0x00007FFFF7BCF850 ; dladdress:
  0x00007FFFF7BC0000 ; offset in lib: 0x000000000000F850 ;
                  (/lib64/libpthread.so.0)
  0x00007FFFE357C741
  _ZN14sqeWLDispDebug7EnterFnEjP15sql_static_data + 0x0029
                  (/home/lpham/sqllib/lib64/libdb2e.so.1)
  </StackTrace>
  

Local fix

• 1) db2set DB2_ALTERNATE_STACK_SIZE=131072
  2) dbstop
  3) db2start
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Linux (AMD64/Intel)                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply v11.1 Mod4 Fixpack 6 to the server.                    *
  ****************************************************************
  

Problem conclusion

• First fixed in v11.1 Mod4 Fixpack 6.
  

Temporary fix

• SEE LOCAL 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