Memory corruption message in db2diag.log, application fails,
Instance services
db2diag.log entries:-
----------------------
2011-04-20-09.02.15.137242+060 I24164020A1473 LEVEL: Severe
PID : 737418 TID : 1 PROC : db2bp
INSTANCE: pi3snap NODE : 000
APPID : *LOCAL.pi3snap.110419110035
EDUID : 1
FUNCTION: DB2 UDB, SQO Memory Management,
sqloDiagnoseFreeBlockFailure,
probe:10
MESSAGE : Possible memory corruption detected.
DATA #1 : ZRC, PD_TYPE_ZRC, 4 bytes
0x820F0002
DATA #2 : Corrupt block address, PD_TYPE_CORRUPT_BLK_PTR, 8
bytes
0x000000011014d500
DATA #3 : Block header, PD_TYPE_BLK_HEADER, 24 bytes
0x000000011014D4E8 : 0000 0000 0000 0000 0000 0000 0000 0000
................
0x000000011014D4F8 : 0000 0000 0000 0000
........
DATA #4 : Data header, PD_TYPE_BLK_DATA_HEAD, 48 bytes
0x000000011014D500 : 0000 0000 0000 0000 0000 0000 0000 0000
................
0x000000011014D510 : 0000 0000 0000 0000 0000 0000 0000 0000
................
0x000000011014D520 : 0000 0000 0000 0000 0000 0000 0000 0000
................
CALLSTCK:
[0] 0x09000000033A2084 pdLog + 0x88
[1] 0x0900000002F10018
@28@sqloDiagnoseFreeBlockFailure__FP8SMemFBlk
+ 0x15C
[2] 0x09000000030CE274 sqlofmblkEx + 0x568
[3] 0x0900000002ED4054 clpPostLoadFreeDynMem + 0xA0
[4] 0x000000010003B858 clpbp_exe_sqluload__Fv + 0x138
[5] 0x0000000100001658 clp_bp_con__Fv + 0x638
[6] 0x0000000100000A84 main + 0x204
[7] 0x0000000100000320 __start + 0x98
[8] 0x0000000000000000 ?unknown + 0x0
[9] 0x0000000000000000 ?unknown + 0x0
---------------------------------------------------------------
The issue happened because once the memory was allocated
successfully and also de-allocated by OSS, then clp tried
freeing the same memory. CLP did not actually allocate the
memory block.
Traces are confirming it:
1511461 | | | sqlage_prepare_sqlca exit
1511464 | | clp_prep_sqlca exit
1511475 | | clpgendb2loadstruct entry
1511481 | | clpgendb2loadstruct exit
1511487 | | clp_send_cmdcb entry
The memory that clp tried freeing was allocated by OSS while it
was writing to the queue and OSS freed it after the write was
successful.
Free:
1512220 | | | | | sqlowqueInternal entry
1512241 | | | | | sqlowqueInternal exit
1512243 | | | | | sqlofmblkEx entry
1512250 | | | | | sqlofmblkEx mbt
[Marker:PD_OSS_FREED_MEMORY ]
1512264 | | | | | sqlofmblkEx exit
1512269 | | | | sqlowque exit
1512278 | | | clp_wque
1512243 entry DB2 UDB SQO Memory Management sqlofmblkEx cei
(1.3.129.33.2)
pid 1970186 tid 1 cpid 37690 node 0 sec 0 nsec 343426849
bytes 50
Data1 (PD_TYPE_PTR,8) Pointer:
0x00000001103d2080
Data2 (PD_TYPE_OSS_MEM_FILE_NAME,10) File name:
sqloqaix.C
Data3 (PD_TYPE_OSS_MEM_LINE_NUM,8) Line of code:
2147
1512250 mbt DB2 UDB SQO Memory Management sqlofmblkEx cei
(6.3.129.33.2.32770)
pid 1970186 tid 1 cpid 37690 node 0 sec 0 nsec 343427962
Marker:PD_OSS_FREED_MEMORY
Description: Freeing memory
bytes 16
Data1 (PD_TYPE_PTR,8) Pointer:
0x00000001103d2080
1512264 exit DB2 UDB SQO Memory Management sqlofmblkEx cei
(2.3.129.33.2)
pid 1970186 tid 1 cpid 37690 node 0 sec 0 nsec 343428923
rc = 0 |
