Fixes are available
APAR status
Closed as program error.
Error description
The WebSphere MQ Explorer is hanging and loosing the WebSphere MQ File Transfer Edition transfer log. The FDC files generated at the time of the hang indicate "Failed to create content page." The probe id for MQ is JU:40010. The problem is only seen when WebSphere MQ tracing is enabled. Even then, the hang is mainly experienced when wrapping trace is used.
Local fix
Avoid running a wrapping WebSphere MQ trace.
Problem summary
**************************************************************** USERS AFFECTED: All users of WebSphere MQ on the Windows platform who enable wrapping trace. Platforms affected: Windows **************************************************************** PROBLEM SUMMARY: The problem occurs due to a deadlock between two threads as follows: 1) Thread A has just entered DllMain in the transaction manager component on Windows (amqmtmgr) and is attempting to write a trace point. As a result, it currently holds the loader lock (because it is in DllMain) and is blocked waiting on the trace lock to become available. 2) Meanwhile, thread B has already entered a trace point and grabs the trace lock. At this point, it determines that it is now time for the trace files to wrap so it attempts to write a new trace file header. The trace header includes some OS specific data retrieved from function xcsGetHostInfo. This includes attempts to load system library kernel32.dll and so, it attempts to acquire the loader lock. However, thread A already has the loader lock hence the deadlock. Even with trace, the problem should not occur very often as it relies on a timing window where the trace files are wrapped at the same time as another thread is entering DllMain for one of the MQ dlls.
Problem conclusion
Code change ensures that the deadlock does not occur between the threads thus preventing the hang in the application process. --------------------------------------------------------------- The fix is targeted for delivery in the following PTFs: v7.0 Platform Fix Pack 7.0.1.3 -------- -------------------- Windows U200320 The latest available maintenance can be obtained from 'WebSphere MQ Recommended Fixes' http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037 If the maintenance level is not yet available, information on its planned availability can be found in 'WebSphere MQ Planned Maintenance Release Dates' http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309 ---------------------------------------------------------------
Temporary fix
Comments
APAR Information
APAR number
IC69703
Reported component name
WMQ WINDOWS V7
Reported component ID
5724H7220
Reported release
701
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2010-07-06
Closed date
2010-07-20
Last modified date
2010-07-20
APAR is sysrouted FROM one or more of the following:
IC68773
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
WMQ WINDOWS V7
Fixed component ID
5724H7220
Applicable component levels
R701 PSY
UP
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Document Information
Modified date:
31 March 2023