A fix is available
APAR status
Closed as unreproducible.
Error description
Receive the following error: . DFHSM0002 A SEVERE ERROR (CODE X'0305') HAS OCCURRED IN MODULE DFHSMGF . The problem is that the failing TASK did a Getmain for KESTK24E for Address 006B3000 and then tried to Freemain 31-bit Address 6B300029. . You can see the following Entries in Trace: . 0302 SMGF EXIT - FUNCTION(GETMAIN) RESPONSE(OK) ADDRESS(006B3000) . 0301 SMGF ENTRY - FUNCTION(FREEMAIN) SUBPOOL_TOKEN(2B42D2F0 , 0000001B) ADDRESS(6B300029) FREE_LENGTH(1000) REMARK(KESTK24E) . The problem is exposed by a storage shortage below 16M. The trace shows several INSUFFICIENT_STORAGE errors just before the freemain error. At some point, there was a failed getmain for 24-bit stack storage. This meant that a task allocated a reserve segment from the emergency kcb_seg24_reserve chain. Because of this the count of reserve elements dropped below 8. Later on, a newly attached task ran through DFHKEXM and tried to getmain a new segment to replenish the reserve chain. This task lost control on the SMLOCK. A second newly attached task also executed code in DFHKEXM and this task issued the same getmain and also lost control on the SMLOCK. Eventually, the first task completed it;s getmain and the reserve count of 24-bit stack segments was once again 8. When the second DFHKEXM task completed it's getmain, it detected that the reserve count was already 8 so it called release_reserve_24_segment to freemain the redundant 24-bit segment. release_reserve_24_segment is passed seg_ptr as the address to be freemained. This a ptr(24) 3-byte pointer. However, release_reserve_24_segment is expecting a ptr(31) 4-byte pointer. This explains the error in the freemain address. . KIXREVEPH Additional Symptom(s) Search Keyword(s):
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All * **************************************************************** * PROBLEM DESCRIPTION: MSGDFHSM0002 severe error code 0305 * * when issuing a KESTK24E freemain. * **************************************************************** * RECOMMENDATION: * **************************************************************** DFHKEXM contains code to getmain segment storage below the 16-megabyte line if the number of available segments falls below a certain threshold. Two tasks executed getmains from DFHKEXM (which is only called during transaction initialization). The first lost control on the storage manager lock which allowed the second task to run and issue a second getmain from DFHKEXM. The second task then lost control, allowing the first task to run again. The first task completed its getmain which brought the number of available segments back to the threshold value. When the second getmain completed, DFHKEXM detected that the segment storage was no longer required so called a routine to freemain the segment, passing a 24-bit pointer to the storage element. The freemain routine expected a 31-bit pointer and consequently the address passed to storage manager was invalid. This caused message DFHSM0002. Additional keywords :- SM0002
Problem conclusion
Temporary fix
FIX AVAILABLE BY PTF ONLY
Comments
DFHKEXM has been changed to use a 31-bit pointer when addressing segment storage.
APAR Information
APAR number
PM62672
Reported component name
CICS TS Z/OS V4
Reported component ID
5655S9700
Reported release
600
Status
CLOSED UR3
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2012-04-17
Closed date
2012-05-11
Last modified date
2012-06-03
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK78672
Modules/Macros
DFHKEXM
Fix information
Fixed component name
CICS TS Z/OS V4
Fixed component ID
5655S9700
Applicable component levels
R600 PSY UK78672
UP12/05/19 P F205
Fix is available
Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.
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Document Information
Modified date:
03 June 2012