A fix is available
APAR status
Closed as program error.
Error description
The QDIO Accelerator function that is accelerating Sysplex Distributed traffic with an associated VIPAROUTE or traffic with divergent outbound interfaces may require the use of pre-staged storage. If the pre-staged storage becomes exhausted the accelerating logic forces any additional packets presented in the inbound buffer up through the normal TCP/IP inbound path. A portion of the accelerating code path is being erroneously executed after the decision to force the normal inbound path has been made. The errant accelerating code traverses the remaining inbound packets and there is a potential loss of data that may occur during this traversal process if a specific data pattern exists. If the packet(s) with lost data requires IP forwarding by the normal inbound path the lost data will be detected by the destination TCP/IP, resulting in the packet(s) being discarded. If the packet(s) with lost data has a final destination of the local TCP/IP stack the lost data will not be detected and the packet(s) payload will be presented to the socket connection. The pre-staged storage is a special pool of storage that is made available for disabled code paths. When the pool becomes exhausted an enabled processes is started to replenish the pool. The pool management provides no external notification of the state of the pool. When the pool becomes exhausted there are no messages issued or any other form of external notification.
Local fix
Disable the QDIO Accelerator function using the IP Sys Admin Command, VARY TCPIP,,OBEYFILE. 1. Create a data set that contains the following TCP/IP profile configuration statement. IPCONFIG NOQDIOACCELERATOR 2. Issue the OBEYFILE command to dynamically change the TCP/IP configuration without stopping and restarting the TCP/IP address space. V TCPIP,tcpproc,O,datasetname 3. Update the existing TCP/IP profile configuration data set to disable QDIO Accelerator in the event TCP/IP is stopped and restarted. Change QDIOACCELerator to NOQDIOACCELerator and delete the optional QDIOPriority if present. or Delete QDIOACCELerator and delete the optional QDIOPriority if present.
Problem summary
**************************************************************** * USERS AFFECTED: All users of the IBM Communications Server * * for z/OS Version 1 Releases 11, 12 and 13 * * IP: QDIO Accelerator and Hipersockets * * Accelerator * **************************************************************** * PROBLEM DESCRIPTION: Potential loss of data following * * exhaustion of pre-staged storage * * for QDIO accelerator. * **************************************************************** * RECOMMENDATION: * **************************************************************** A pre-staged storage pool used by the QDIO/HiperSockets accelerator became constrained. An asynchronous storage management process, running as an enabled thread, was started to replenish this pool. During the time interval the storage pool was exhausted, the accelerator exit performed incorrect processing on some remaining inbound packets that held a specific data pattern. The error in processing resulted in the subsequent loss of data. The problem is possible for configurations using: - QDIO Accelerator with Sysplex Distributer - QDIO Accelerator with non-Sysplex Distributer - HiperSockets Accelerator (i.e.IQDIOROUTING) The problem does not occur when the Accelerator function is disabled. +-------------------------------------------------------------+ + 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
Module EZBIFQDR (the Accelerator Routing Exit) has been amended to correctly process inbound packets following exhaustion of the pre-staged storage pool. * Cross Reference between External and Internal Names
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
PM37396
Reported component name
TCP/IP V3 MVS
Reported component ID
5655HAL00
Reported release
1B0
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2011-04-19
Closed date
2011-04-21
Last modified date
2011-06-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK66995 106PC1 106PC1 UK66996 106PC1 106PC1 106PC1 UK66997
106PC1 106PC1 106PC1
Modules/Macros
EZBIFQDR
Fix information
Fixed component name
TCP/IP V3 MVS
Fixed component ID
5655HAL00
Applicable component levels
R1B0 PSY UK66995
UP11/05/04 P F105
R1C0 PSY UK66996
UP11/05/18 P F105
R1D0 PSY UK66997
UP11/05/19 P F105
Fix is available
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Document Information
Modified date:
02 June 2011