APAR status
Closed as unreproducible in next release.
Error description
With channel statistics enabled on a SVRCONN channel with a channel exit in place and using the async consume feature the amqrmppa process crashes with a memory exception. The issue does not occur if a channel exit is not in place and channel statistics are enabled. The issue also does not occur if a channel exit is in place and channel statistics are not enabled. Failure Data Capture (FDC) records will be generated and example FDCs on UNIX/LINUX platforms would present the following Probe ID, component, comment and call stack. Probe Id: XC130003 Component: xehExceptionHandler Comment1: SIGSEGV: address not mapped(0x64) O/S Call Stack for current thread: /opt/mqm/lib64/libmqmcs_r.so(xcsPrintStackForCurrentThread+0x3e) 71b8bce] /opt/mqm/lib64/libmqmcs_r.so(+0x11537a) /opt/mqm/lib64/libmqmcs_r.so(PrepareDumpAreas+0xc07) /opt/mqm/lib64/libmqmcs_r.so(xcsFFSTFn+0xb75) /opt/mqm/lib64/libmqmcs_r.so(xehExceptionHandler+0x705) /usr/lib64/libpthread.so.0(+0xf5e0) /opt/mqm/lib64/libmqmr_r.so(rriCallSndExit+0xb9c /opt/mqm/lib64/libmqmr_r.so(rstSendAsyncMessage+0x411) /opt/mqm/lib64/libmqmr_r.so(rstConsumer+0xbe4) /opt/mqm/lib64/libmqzi_r.so(zstUserCallback+0x23a) /opt/mqm/lib64/libmqzi_r.so(zstAsyncConsume+0x1786) /opt/mqm/lib64/libmqzi_r.so(zstAsyncConsumeThread+0x5ab) /opt/mqm/lib64/libmqmcs_r.so(+0x16e93e) /usr/lib64/libpthread.so.0(+0x7e25) /usr/lib64/libc.so.6(clone+0x6d) MQM Function Stack zstAsyncConsumeThread zstAsyncConsume zstUserCallback zstConsumerFunction rstConsumer rstSendAsyncMessage rriCallSndExit xcsFFST ... Probe Id: RM052101 Component: rriCallSndExit Probe Type: HALT6109 On Windows, the amqrmppa process might crash with no FDC or with FDC XC130031. The stack trace extracted from the process dump file is likely to show the following call stack. 00 03f7f774 100f7d04 amqrdlla!rriCallSndExit+0xc6b 01 03f7f808 100f623a amqrdlla!rstSendAsyncMessage+0x894 02 03f7f888 00274447 amqrdlla!rstConsumer+0xc0a 03 03f7fab8 0027740e amqzi!zstUserCallback+0x537 04 03f7fe3c 00000000 amqzi!zstAsyncConsume+0x232e
Local fix
Making one of the following changes and then restarting the affected client applications likely to workaround the problem. * Disable Channel statistics * Disable exit * Set SHARECNV to 0 * If the client application is not using asynchronous consume feature set SHARECNV to 1
Problem summary
**************************************************************** USERS AFFECTED: * Users using a SVRCONN channel with an exit, the asynchronous consume feature and channel statistics enabled. If any one of these 3 elements is removed from the channel configuration or scenario, the issue is not observed. * Users using SHARECNV > 0 with SVRCONN channel exit and channel statistics enabled in MQ 7.x * Users using SHARECNV > 1 with SVRCONN channel exit and channel statistics enabled in MQ 8.0 and higher MQ versions * Users using SHARECNV = 1 with clients using async consume feature and SVRCONN channel exit and channel statistics enabled in MQ 8.0 and higher MQ versions might be affected by this problem. * Users using SHARECNV = 0 are not affected by this problem Platforms affected: MultiPlatform **************************************************************** PROBLEM DESCRIPTION: A design limitation of the SVRCONN channel implementation prior to MQ 9.1.2 meant that a potentially unsafe access was made to the channel status table in the scenario described above.
Problem conclusion
Design changes introduced in IBM MQ 9.1.2 have altered the implementation of SVRCONN channels such that this issue can no longer be encountered in this scenario.
Temporary fix
Comments
APAR Information
APAR number
IT22101
Reported component name
WMQ BASE MULTIP
Reported component ID
5724H7241
Reported release
750
Status
CLOSED UR1
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2017-08-22
Closed date
2019-07-11
Last modified date
2019-08-29
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
WMQ BASE MULTIP
Fixed component ID
5724H7241
Applicable component levels
[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSDEZSF","label":"IBM WebSphere MQ Managed File Transfer for z\/OS"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.5","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}}]
Document Information
Modified date:
31 March 2023