This Service Bulletin contains important information regarding the recommended procedure to be followed when applying either PJ36227 from TPF4.1 PUT 24 or PJ36514 from z/TPF 1.1 PUT 6. This information applies to users who have not yet installed these APARs or any customer who needs to remove one of these APARs.
Resolving the problem
TPF 4.1 APAR PJ36227 and z/TPF APAR PJ36514 introduce changes to MQ trace logging that do not coexist with the pre-APAR MQ trace logic. Before activating a load that contains these APARs, turn off MQ trace. Restart MQ trace when all of the ECBs are running on the new activation number. If you need to fall back (deactivate the APAR), complete the following steps:
- Turn off MQ trace.
- Stop all MQ channels.
- Deactivate the loadset.
- When the deactivation completes, restart the channels and restart MQ channel trace.
The problem introduced by PJ36227 and PJ36514 is that two different versions of the trace program are running during the load process. Each accesses the same trace message counter; however, they use different methods for updating the counter. Before you install the APARs, the trace block will be written only if the count is equal to 6. With the APAR applied the block will be written if the count is greater than or equal to 7. With both copies of the code running concurrently the potential exists that the counter will be greater than 6. This situation is not handled by the older (pre-APAR) code, which results in trace entries written past the end of the system heap block and corruption of system storage.If you have any questions or concerns about the information in this service bulletin, send an e-mail to TPFQA@US.IBM.COM