A fix is available
APAR status
Closed as program error.
Error description
ABEND4C5 rc742E0402 in EZBIPRHD due to a RTOP with an unbalanced RtpRteCount and RtpUseCount. The RTOP RtpRteCount is zero and the RtpUseCount is 2 indicating something is wrong in the referencing of the RTOP. The problem stems from the removal of a destination cache entry in the routing tree. A timing condition exists where the destination cache entry is being removed at the same time that it is located and referenced for reuse. Destination cache entries are created for IPv6 network traffic and IPv4 when PATHMTUDISCOVERY or VIPAROUTE are enabled.
Local fix
Disable PATHMTUDISCOVERY on the IPCONFIG statement in the TCP/IP profile. This can be done dynamically using the VARY TCPIP,tcpname,Obeyfile,datasetname command where the dataset contains: IPCONFIG NOPATHMTUDISCOVERY Disable VIPAROUTE on the VIPADYNAMIC block in the TCP/IP profile. This can be done dynamically using the VARY TCPIP,tcpname,Obeyfile,datasetname command where the dataset contains: VIPADYNAMIC VIPAROUTE DELETE dynxcfip target_ipaddr ENDVIPADYNAMIC The removal of VIPAROUTE will cause any distributed traffic to be forwarded over internal XCF or IQDIO links. ADDITIONAL SYMPTOMS: ABEND0C4 in EZBIPRTE caused by the routing tree becoming corrupted. ABEND4C5 EZBXFUT3 Reason 77BB0402 . ABEND0C4 in EZBIPRHD - PTREEPOINTUP ABEND0C4 in EZBIPRHD ABEND4C5 RC 76803003 - TcpSTKPTreeRecover ABEND4C5 RC 74BE2506 - TcpitStorNotAllocated ABEND0C4 in EZBXFMS6 during TERMCONN processing due to an invalid XFCRHTE_RTE pointer. The TERMCONN processing is identifying the CRHTE to be removed and the CRHTE address is bad. KEYWORDS: AB4C5 ABs4C5 ABENDs0C4 4C5 0C4 rc76803003 3003 742E0402 0402 TcpUnexpectedErr PATHMTUDISCOVERY VIPAROUTE
Problem summary
**************************************************************** * USERS AFFECTED: All users of the IBM Communications Server * * for z/OS Version 1 Release(s) 11, 12, * * and 13 IP * **************************************************************** * PROBLEM DESCRIPTION: Various abends in route management * * modules accessing a route that has been * * deleted. Abends may also occur in * * modules unrelated to route management * * due to possible storage corruption. * **************************************************************** * RECOMMENDATION: * **************************************************************** Various abends in route management modules accessing a route that has been deleted. Abends may also occur in modules unrelated to route management due to possible storage corruption. Destination cache entries are special purpose structures added to the routing trees for IPv6 traffic, and IPv4 traffic when PathMTUdiscovery is enabled, or VIPAROUTE is enabled for Sysplex distributor. A garbage collection routine periodically runs and deletes any stale destination cache entries that are no longer in use. The delete occurs in the update copy of the routing tree, then the search copy of the routing tree. The reference count maintained in the destination cache entry is incorrectly decremented before the entry has been removed from the search tree. A timing window exists where a searcher can find the deleted destination cache entry and use it after the associated storage has been returned to the storage cache queue for reuse. The searcher will update the reference count and when the destination cache is no longer needed it will decrement the reference count. The storage where the destination cache entry resided may be used for another route structure or any other storage request that has a similar size. The reference count update logic may detect an error condition and generate an ABEND4C5 in one of the routing modules, or the update may be performed without detecting an error with unpredictable results. The final reference to the destination cache entry should not be removed until the trees have been swapped and the search tree has been updated. +-------------------------------------------------------------+ + 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
EZBIPDDC and EZB6PDDC have been amended to maintain a reference count on deleted destination cache entries until the routing trees have been successfully swapped. * Cross Reference between External and Internal Names
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
PM57513
Reported component name
TCP/IP V3 MVS
Reported component ID
5655HAL00
Reported release
1C0
Status
CLOSED PER
PE
YesPE
HIPER
YesHIPER
Special Attention
NoSpecatt
Submitted date
2012-02-06
Closed date
2012-03-05
Last modified date
2012-05-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK76838 UK76839 UK76840
Modules/Macros
EZBIPRTE EZB6PRTE
Fix information
Fixed component name
TCP/IP V3 MVS
Fixed component ID
5655HAL00
Applicable component levels
R1B0 PSY UK76838
UP12/04/03 P F204 ®
R1C0 PSY UK76839
UP12/04/03 P F204 ®
R1D0 PSY UK76840
UP12/04/03 P F204 ®
Fix is available
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Document Information
Modified date:
02 May 2012