PI69625: LIBERTY SERVER AT 16.0.0.3 MAY FAIL TO START WHEN USING ASYNCIO

Fixes are available

APAR status

Closed as program error.

Error description

16.0.0.3 provides Asynchronous TCP/IP sockets I/O for Liberty
on z/OS.  When this is enabled (by permitting the server to
RACF server class BBG.AUTHMOD.BBGZSAFM.ZOSAIO and running the
Angel process), the server tries to allocate 2GB of above the
bar storage use in one of its pools.  If the storage obtain
fails, the code doesn't handle this failure correctly and takes
a gpf (abend0C4) causing the server to fail to start.
This may also happen after startup, if another buffer is
needed, but there not enough memory for the additional buffer.
The messages.log will show this is enabled:
CWWKB0103I: Authorized service group ZOSAIO is available
java core will show this as the current thread:
"LargeThreadPool-thread-2"
Java callstack:
at com/ibm/io/async/AsyncLibrary.aio_init(Native Method)
at com/ibm/io/async/AsyncLibrary.initialize(Bytecode PC:33)
at com/ibm/io/async/AsyncLibrary.(Bytecode PC:37)
at com/ibm/io/async/AsyncLibrary.
createInstance(BytecodePC:64)
com/ibm/ws/tcpchannel/internal/AioTCPChannel.
setup(Bytecode PC:35)
at com/ibm/ws/tcpchannel/internal/TCPChannelFactory.
createChannel(Bytecode PC:74)

Local fix

There are a few workarounds that can be used
1. Disable Asynchronous TCP/IP sockets I/O for Liberty on z/OS
for the server by removing the server's access to RACF server
class BBG.AUTHMOD.BBGZSAFM.ZOSAIO
2. Disable Asynchronous TCP/IP sockets I/O for Liberty on z/OS
for the server by adding the following property to the
bootstrap.properties file:
com.ibm.ws.tcpchannel.useZosAio=false
3.  Adjust restrictions on memory usage for the server to allow
the 2GB allocation to succeed.  This can be done by adding
MEMLIMIT=NOLMIT to the server proc.

Problem summary

****************************************************************
* USERS AFFECTED:  All users of IBM WebSphere Application      *
*                  Server Liberty for z/OS                     *
****************************************************************
* PROBLEM DESCRIPTION: An ABEND0C4 can occur in native routine *
*                      buildCellPool on address                *
*                      x'00000000_7FFFF000' returned from a    *
*                      failed IARV64 GetStor call.             *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
The initialization code related to the
z/OS Asynchronous I/O TCP (AsyncIO) support failed to obtain a
roughly 2Gig, above the bar, piece of storage for use in one of
its
pools.  The code failed to check the return code from the IARV64
GETSTOR invocation and instead just checked the returned storage
address.

From the systrace I see:

0002 0221 008C4328  SSRV   14B          01C42020
  00000008 4A001620 00000000  IarV64   GetStor
  00000000_7FFFF000
00000000_000007CF
00000000_00000000

The systrace entry above shows a return code of 8 and rsn of
x'0016'.
It also shows the return storage address of
x'00000000_7FFFF000'.

The AsyncIO code checked for a non-zero returned storage address
and
attempted to use the x'00000000_7FFFF000' as its storage.  The
ABENDS0C4 resulted when attempting to format the storage within
the
buildCellPool routine called from buildAIOSRBCellPool within
the mvs_aio_services module.

Problem conclusion

Code has been modified in the Asynchronous
I/O (AsyncIO) cellpool management code to
verify that storage was obtained prior to use.
Also, code was added to dynamically grow the
AsyncIO SRB cellpool as needed.  This eliminates
the initial 2Gig storage allocation for a
static cellpool.

The fix for this APAR is currently targeted for inclusion in fix
pack 16.0.0.4.  Please refer to the Recommended Updates page for
delivery information:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980

Temporary fix

Comments

APAR Information

APAR number
PI69625
Reported component name
LIBERTY PROF -
Reported component ID
5655W6514
Reported release
CD0
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2016-09-22
Closed date
2016-10-18
Last modified date
2016-11-03

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
LIBERTY PROF -
Fixed component ID
5655W6514

Applicable component levels

RCD0 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":"CD0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
04 May 2022

Tips

PI69625: LIBERTY SERVER AT 16.0.0.3 MAY FAIL TO START WHEN USING ASYNCIO

Fixes are available

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APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

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

Fixed component ID

Applicable component levels

RCD0 PSY

Document Information

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