A fix is available
APAR status
Closed as program error.
Error description
During shutdown, the queue manager tries to put an event message to a cluster queue defined on another queue manager. The cluster channel was in a get-wait on the SYSTEM.CLUSTER.TRANSMIT.QUEUE at the time of the STOP QMGR command and there was an attempt to put the message directly into the getter's buffer. However CHIN shutdown processing posts the channel out of the get-wait at the same time. This results in abend 0C4 in CSQM2PGB and the subsequent abend 0C4 in CSQXADPM.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM MQ for z/OS Version 9 * * Release 0 Modification 0 and Release 1 * * Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: A storage overlay can occur in the * * channel initiator address space if a * * message is put to a transmission queue * * at the same time as the queue manager * * is quiescing. * * Symptoms of the overlay will depend on * * how the overlaid storage is used, and * * can include abend 0C4 in CSQXADPM. * **************************************************************** A channel with NPMSPEED(FAST) was waiting for a message to arrive on the transmission queue when the queue manager was quiesced. CSQXDSPT posted the channel with MQEC_CONNECTION_QUIESCING, allowing the channel to leave CSQXADPM and start termination processing. However, until the channel closes the transmission queue, the handle remains on the get wait chain. If a non-persistent message is put out of syncpoint to the queue, it is eligible to be put directly to the getter's buffer - this was in CSQXADPM's working storage, which could have been reused by other routines called by the channel, leading to unpredictable behaviour.
Problem conclusion
CSQXADPM is changed to cancel the getwait request, removing the handle from the getwait chain, prior to returning when posted with MQEC_CONNECTION_QUIESCING.
Temporary fix
Comments
APAR Information
APAR number
PH05919
Reported component name
IBM MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
000
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2018-11-29
Closed date
2019-01-04
Last modified date
2019-02-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI60519 UI60520
Modules/Macros
CSQXADPM
Fix information
Fixed component name
IBM MQ Z/OS V9
Fixed component ID
5655MQ900
Applicable component levels
Fix is available
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Document Information
Modified date:
02 February 2019