Fixes are available
8.0.0.7: WebSphere Application Server V8.0 Fix Pack 7
8.0.0.8: WebSphere Application Server V8.0 Fix Pack 8
8.0.0.9: WebSphere Application Server V8.0 Fix Pack 9
8.0.0.10: WebSphere Application Server V8.0 Fix Pack 10
8.0.0.11: WebSphere Application Server V8.0 Fix Pack 11
8.0.0.12: WebSphere Application Server V8.0 Fix Pack 12
8.0.0.13: WebSphere Application Server V8.0 Fix Pack 13
8.0.0.14: WebSphere Application Server V8.0 Fix Pack 14
8.0.0.15: WebSphere Application Server V8.0 Fix Pack 15
APAR status
Closed as program error.
Error description
Connections in the control region are not cleaned up properly when an unexpected exception is received completing an asynchronous read. Netstat conn will show connections for the control region in CLOSEWAIT. An example of an unexpected exception is this FFDC: FFDC Exception:java.lang.NullPointerException SourceId:com.ibm.ws.tcp.channel.ZAioTCPChannel ProbeId:300 Reporter:com.ibm.ws.tcp.channel.impl.ZAioTCPChannel@11c3b761 java.lang.NullPointerException at com.ibm.ws390.xmem.proxy.channel.XMemProxyCRInboundConnLink. destroyCommon(XMemProxyCRInboundConnLink.java:301) at com.ibm.ws390.xmem.proxy.channel.XMemProxyCRInboundConnLink. destroy(XMemProxyCRInboundConnLink.java:285) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink. destroy(HttpInboundLink.java:158) at com.ibm.wsspi.channel.base.OutboundConnectorLink. destroy(OutboundConnectorLink.java:63) at com.ibm.ws.tcp.channel.impl.ZAioTCPConnLink. destroyCommon(ZAioTCPConnLink.java:1060) at com.ibm.ws.tcp.channel.impl.ZAioTCPConnLink. destroy(ZAioTCPConnLink.java:1020) at com.ibm.wsspi.channel.base.OutboundConnectorLink. close(OutboundConnectorLink.java:50) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink. close(HttpInboundLink.java:781) at com.ibm.ws.http.channel.inbound.impl.HttpICLReadCallback. error(HttpICLReadCallback.java:134) at com.ibm.ws.tcp.channel.impl.ZAioTCPReadRequestContextImpl. readCompleted(ZAioTCPReadRequestContextImpl.java:750) at com.ibm.ws.tcp.channel.impl.ZAioTCPConnLink. readCompleted(ZAioTCPConnLink.java:1206) at com.ibm.ws.tcp.channel.impl.ZAioTCPChannel. readCompleted(ZAioTCPChannel.java:929) at com.ibm.ws.tcp.channel.impl.ZAioTCPChannelCPPUtilities. readCompleted(ZAioTCPChannelCPPUtilities.java:181) KEYWORDS: CLOSWAIT CLOSE_WAIT CLOS_WAIT socket sockets connection
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM WebSphere Application * * Server V8.0 and V8.5 * **************************************************************** * PROBLEM DESCRIPTION: A java.lang.NullPointerException can * * occur in a WebSphere Application * * Server for z/OS Controller when * * asynchronous I/O operations complete * * at the same time the connection is * * being destroyed. * **************************************************************** * RECOMMENDATION: * **************************************************************** The following java.lang.NullPointerException is observed in a WebSphere Application Server for z/OS Controller: SourceId:com.ibm.ws.tcp.channel.ZAioTCPChannel ProbeId:300 java.lang.NullPointerException at com.ibm.ws.tcp.channel.impl.ZAioTCPConnLink.readCompleted (ZAioTCPConnLink.java:1197) at com.ibm.ws.tcp.channel.impl.ZAioTCPChannel.readCompleted (ZAioTCPChannel.java:929) at com.ibm.ws.tcp.channel.impl.ZAioTCPChannelCPPUtilities. readCompleted(ZAioTCPChannelCPPUtilities.java:181) This problem occurs because an outstanding asynchronous I/O operation (which can be a read or a write) is attempting to complete at the same time that some other thread in the server is attempting to destroy the connection. A timing window exists such that the destruction of the connection sets a field to null and the field is then dereferenced by the I/O completion.
Problem conclusion
Synchronization was added so that I/O completions that are currently being processed are allowed to complete before a connection can be destroyed. APAR PM74747 is currently targeted for inclusion in WebSphere Application Server V8.0 Fix Pack 8.0.0.7 and a Fix Pack 8.5.5 of WebSphere Application Server V8.5.
Temporary fix
Comments
APAR Information
APAR number
PM74747
Reported component name
WEBSPHERE FOR Z
Reported component ID
5655I3500
Reported release
800
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2012-10-10
Closed date
2013-03-13
Last modified date
2013-05-02
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
WEBSPHERE FOR Z
Fixed component ID
5655I3500
Applicable component levels
R800 PSY
UP
[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SS7K4U","label":"WebSphere Application Server for z\/OS"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"800","Line of Business":{"code":"LOB45","label":"Automation"}}]
Document Information
Modified date:
29 October 2021