IC66411: MEMORY CORRUPTION WHEN RUNNING A QUERY WITH SUBQUERY IN A PROCEDURE WHICH USES PDQ

APAR status

• Closed as program error.

Error description

• Running a query with subquery in a procedure which uses PDQ
  causes memory corruption.
  
  The stacks might vary, see examples below:
  
  20:09:02  Assert Failed: Exception Caught. Type: MT_EX_OS,
  Context: mem
  20:09:02  IBM Informix Dynamic Server Version 11.50.FC5W3
  20:09:02   Who: Session(31, informix@myhost, 28705, 4f04283b0)
                  Thread(21242, sqlexec, 4f03ea528, 4)
                  File: mtex.c Line: 417
  20:09:02   Action: Please notify IBM Informix Technical Support.
  20:09:02  stack trace for pid 28659 written to /tmp/af.56e2a746
  20:09:02   See Also: /tmp/af.56e2a746
  20:09:09  Exception Caught. Type: MT_EX_OS, Context: mem
  20:09:10  (-9791): ERROR: Routine execution trap --
  procname=<sp_myproc> procid=552
  
  
  0x100d907fc oninit :: mt_lock
  0x100ded370 oninit :: xchg_next
  0x100362c40 oninit :: getrow
  0x100362898 oninit :: fetchrow
  0x100360bbc oninit :: doselect
  0x10039a4cc oninit :: exsubq
  0x100fa7fdc oninit :: ev_cb
  0x100f9cf70 oninit :: new_eval
  0x1002157d4 oninit :: ip_evalexpr
  0x10021360c oninit :: runproc
  0x1002233ec oninit :: udrlm_spl_execute
  0x100544d2c oninit :: udrlm_exec_routine
  0x1002571c4 oninit :: udr_execute
  0x10025e62c oninit :: exroutine
  0x1004fcc98 oninit :: sq_exproc
  0x10059dd78 oninit :: sqmain
  0x100e6cde4 oninit :: listen_verify
  0x100e6c374 oninit :: spawn_thread
  0x100da27fc oninit :: startup
  
  
  14:15:11  Assert Warning: Memory free block header corruption
  detected in mt_shm_malloc_segid 5
  14:15:11   Who: Session(32, informix@host, 21529, 4f042ae08)
      Thread(59039, scan_1.0, 4f03f6b68, 3)
      File: mtshpool.c Line: 1510
  14:15:11   Results: x,Yz
  14:15:11   Action: Please notify IBM Informix Technical Support.
  14:15:11  Raw hex dump of stack located in
  /tmp/af.ea87545e.rawstk
  14:15:11  Stack for thread: 59039 scan_1.0
  
  0x100e05b28 oninit :: afstack
  0x100e04868 oninit :: afhandler
  0x100e03aa4 oninit :: afwarn_interface
  0x100df27ec oninit :: mt_shm_malloc_segid
  0x100df1720 oninit :: mt_malloc
  0x100186ac0 oninit :: copykeydesc
  0x10026c9e8 oninit :: udrpll_crt_keydesc
  0x100e67364 oninit :: fmstart
  0x100360fdc oninit :: readidx_old
  0x100359fd0 oninit :: gettupl
  0x10035520c oninit :: scan_next
  0x100e1b93c oninit :: producer_thread
  0x100dd4968 oninit :: startup
  
  
  0x100df3434 oninit :: get_drainable
  0x100df3db8 oninit :: mt_free
  0x10082f5c0 oninit :: rstcb_cleanup
  0x100dde1f4 oninit :: exit_thread
  0x100e1c2dc oninit :: producer_thread
  0x100dd4968 oninit :: startup
  
  
  0x100d907fc oninit :: mt_lock
  0x100dec638 oninit :: xchg_close
  0x1001b4730 oninit :: closecb
  0x1001b4348 oninit :: close_cb_subtree_r
  0x1001b4488 oninit :: close_cb_subtree_r
  0x1001b4164 oninit :: close_cb_subtree
  0x1001b3c64 oninit :: closesdb
  0x1001b2fac oninit :: doreleasesdb
  0x10021f928 oninit :: drpcurlist
  0x10025acc0 oninit :: rmstproc
  0x100309c84 oninit :: sqscb_cleanup
  0x100daab68 oninit :: destroy_session
  0x100281ea0 oninit :: sqsetconerr
  0x1005a8e18 oninit :: asf_recv
  0x1005a8edc oninit :: _iread
  0x1005a77d4 oninit :: _igetint
  0x10059db70 oninit :: sqmain
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users having sql tracing set and running SPL or subquery in  *
  * pdq environment                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * When sql tracing is enabled and multiple prepared statements *
  * using subquery or SPL are running in PDQ environment, server *
  * can give crash or memory corruption.                         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to 11.50.xC7 and above.                              *
  ****************************************************************
  

Problem conclusion

• Problem first fixed in 11.50.xC7
  

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

  IBM IDS ENTRP E

• Fixed component ID

  5724L2304

Applicable component levels

• RB15 PSN

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