A fix is available
APAR status
Closed as program error.
Error description
An abend can occur when a pointer is incorrectly assumed to be null following a lock obtain failure. This can prevent a hashtab reference count from being decremented. When the dispatchable unit of work exits the TCP/IP code path the DUCB destroy process detects the residual hashtab reference and issues the S4C5 abend with reason code xxxx2A00.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of the IBM Communications Server * * for z/OS Version 1 Release(s) 11, 12, and * * 13 IP: NETMONITOR TCPCONNSERVICE Network * * Management Interface (NMI) * **************************************************************** * PROBLEM DESCRIPTION: AbendS4C5 rsnxxxx2A00 in the Real-time * * TCP/IP Network Monitoring Interface * * (NMI) when NETMONITOR ON TCPCONNSERVICE * * is specified in the profile at TCP/IP * * start up or activated via OBEYFILE. * **************************************************************** * RECOMMENDATION: * **************************************************************** AbendS4C5 rsnxxxx2A00 in the Real-time TCP/IP Network Monitor Interface (NMI) when NETMONITOR ON TCPCONNSERVICE is specified in the profile at TCP/IP start up or activated via OBEYFILE. The specification of NETMONITOR ON TCPCONNSERVICE causes the Real-time TCP/IP Network Monitoring NMI SYSTCPCN interface task to be attached. The task initialization logic scans the TCP connection table and sets an flag in each active TCB to indicate a notification should be delivered to the NMI when the connection terminates. A timing window exists where a connection is being closed at the same time NMI initialization is attempting to obtain the TCB lock to serialize setting the flag. When this occurs the lock obtain fails but the NMI code tries to incorrectly release the lock again, resulting in an abendS4C5 rsnxxxx2102. The NMI task recovers from the abend and continues to process without performing cleanup on the connection table reference. Later when the NMI task is terminated either from a stop of TCP/IP or an OBEYFILE to set NETMONITOR OFF the abendS4C5 rsnxxxx2A00 occurs when the residual TCP connection table reference is detected. +-------------------------------------------------------------+ + Please check our Communications Server for OS/390 homepages + + for common networking tips and fixes. The URL for these + + homepages can be found in Informational APAR II11334. + +-------------------------------------------------------------+
Problem conclusion
EZBCTTMI has been amended to process the TCB lock correctly and thus avoid the original abends4C5 rsnxxxx2102 that caused the residual TCP connection table reference. * Cross Reference between External and Internal Names
Temporary fix
Comments
APAR Information
APAR number
PM39036
Reported component name
TCP/IP V3 MVS
Reported component ID
5655HAL00
Reported release
1B0
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2011-05-12
Closed date
2011-06-13
Last modified date
2011-08-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK68727 UK68726 UK68728
Modules/Macros
EZBCTTMI
Fix information
Fixed component name
TCP/IP V3 MVS
Fixed component ID
5655HAL00
Applicable component levels
R1B0 PSY UK68726
UP11/07/12 P F107
R1C0 PSY UK68727
UP11/07/12 P F107
R1D0 PSY UK68728
UP11/07/12 P F107
Fix is available
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Document Information
Modified date:
01 August 2011