PM21702: IBM StAX Parser might hang while parsing a large XML document.

Fixes are available

APAR status

Closed as program error.

Error description

In WebSphere Application Server V7, if the IBM StAX
parser is used to parse a large XML document (50 MB or more)
it could hang. This condition might cause the thread to hang.

The thread stack seen when looking at a javacore would look like
this:

com/ibm/xml/xlxp2/scan/util/XMLString$1.hasReferenceTo(XMLString
.java:117(Compiled Code))
at
com/ibm/xml/xlxp2/scan/util/SimpleDataBufferFactory$DataBufferRe
ferrerQueue.isReferenced(SimpleDataBufferFactory.java(Compiled
Code))
at
com/ibm/xml/xlxp2/scan/util/SimpleDataBufferFactory.reclaimBuffe
rs(SimpleDataBufferFactory.java:271(Compiled Code))
at
com/ibm/xml/xlxp2/api/util/encoding/ByteStreamDataSource.load(By
teStreamDataSource.java:210(Compiled Code))
at
com/ibm/xml/xlxp2/scan/util/ParsedEntity.loadMore(ParsedEntity.j
ava:229(Compiled Code))
at
com/ibm/xml/xlxp2/scan/util/ParsedEntity.skipMoreValidXMLBytesUs
ingMapForXMLString(ParsedEntity.java:903(Compiled Code))
at
com/ibm/xml/xlxp2/scan/util/ParsedEntity.scanSimpleContentAcross
Buffers(ParsedEntity.java:1208)
at
com/ibm/xml/xlxp2/scan/util/ParsedEntity.scanSimpleContent(Parse
dEntity.java:1147(Compiled Code))
at
com/ibm/xml/xlxp2/scan/DocumentScanner.scanContent(DocumentScann
er.java:1830(Compiled Code))
at
com/ibm/xml/xlxp2/runtime/VMContext.scanContent(VMContext.java:5
01(Compiled Code))
at
com/ibm/xml/xlxp2/scan/DocumentScanner.nextEvent(DocumentScanner
.java:1276(Compiled Code))
at
com/ibm/xml/xlxp2/api/stax/XMLStreamReaderImpl.next(XMLStreamRea
derImpl.java:579(Compiled Code))
at
com/ibm/xml/xlxp2/api/stax/XMLInputFactoryImpl$XMLStreamReaderPr
oxyImpl.next(XMLInputFactoryImpl.java:183(Compiled Code))
at
com/ibm/xml/xlxp2/api/wssec/WSSXMLInputFactory$WSSStreamReaderPr
oxy.next(WSSXMLInputFactory.java:55(Compiled Code))
at
org/apache/axiom/om/impl/builder/StAXBuilder.parserNext(StAXBuil
der.java:567(Compiled Code))
at
org/apache/axiom/om/impl/builder/StAXOMBuilder.nextToken(StAXOMB
uilder.java:622(Compiled Code))
at
org/apache/axiom/om/impl/builder/StAXOMBuilder.next(StAXOMBuilde
r.java:173(Compiled Code))
at
org/apache/axiom/om/impl/llom/OMElementImpl.getNextOMSibling(OME
lementImpl.java:337(Compiled Code))
at
org/apache/axiom/om/impl/traverse/OMChildrenIterator.next(OMChil
drenIterator.java:106)
...

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  All IBM WebSphere Application Server V7.0   *
*                  users of StAX, JAXB and JAX-WS.             *
****************************************************************
* PROBLEM DESCRIPTION: Parsing a large XML document with the   *
*                      IBM StAX parser may cause a thread to   *
*                      hang.                                   *
****************************************************************
* RECOMMENDATION:  Install a fix pack that contains this APAR. *
****************************************************************
Parsing a large XML document (in the range of 50 MB or more)
with the IBM StAX parser (XMLStreamReader) may cause the
thread it is executing on to hang.

The thread's stack when looking at it in a debugger or
javacore file may look like the following:

com/ibm/xml/xlxp2/scan/util/XMLString$1.hasReferenceTo(XMLString
.java:117(Compiled Code))
at
com/ibm/xml/xlxp2/scan/util/SimpleDataBufferFactory$DataBufferRe
ferrerQueue.isReferenced(SimpleDataBufferFactory.java(Compiled
Code))
at
com/ibm/xml/xlxp2/scan/util/SimpleDataBufferFactory.reclaimBuffe
rs(SimpleDataBufferFactory.java:271(Compiled Code))
at
com/ibm/xml/xlxp2/api/util/encoding/ByteStreamDataSource.load(By
teStreamDataSource.java:210(Compiled Code))
at
com/ibm/xml/xlxp2/scan/util/ParsedEntity.loadMore(ParsedEntity.j
ava:229(Compiled Code))
at
com/ibm/xml/xlxp2/scan/util/ParsedEntity.skipMoreValidXMLBytesUs
ingMapForXMLString(ParsedEntity.java:903(Compiled Code))
at
com/ibm/xml/xlxp2/scan/util/ParsedEntity.scanSimpleContentAcross
Buffers(ParsedEntity.java:1208)
at
com/ibm/xml/xlxp2/scan/util/ParsedEntity.scanSimpleContent(Parse
dEntity.java:1147(Compiled Code))
at
com/ibm/xml/xlxp2/scan/DocumentScanner.scanContent(DocumentScann
er.java:1830(Compiled Code))
at
com/ibm/xml/xlxp2/runtime/VMContext.scanContent(VMContext.java:5
01(Compiled Code))
at
com/ibm/xml/xlxp2/scan/DocumentScanner.nextEvent(DocumentScanner
.java:1276(Compiled Code))
at
com/ibm/xml/xlxp2/api/stax/XMLStreamReaderImpl.next(XMLStreamRea
derImpl.java:579(Compiled Code))
at
com/ibm/xml/xlxp2/api/stax/XMLInputFactoryImpl$XMLStreamReaderPr
oxyImpl.next(XMLInputFactoryImpl.java:183(Compiled Code))
at
com/ibm/xml/xlxp2/api/wssec/WSSXMLInputFactory$WSSStreamReaderPr
oxy.next(WSSXMLInputFactory.java:55(Compiled Code))
...

Problem conclusion

For efficiency, the IBM StAX parser will try to reuse
input buffers which contain portions of the XML document that
have already been processed. For a large document (in the
range of 50 MB or more) these repeated attempts to recycle the
input buffers could cause the thread to hang.

This problem is resolved by improving the algorithm used for
recycling input buffers, so that the checks for freeing buffers
are made less frequently.

The fix for this APAR is currently targeted for inclusion in
fix pack 7.0.0.15.  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
PM21702
Reported component name
WEBSPHERE APP S
Reported component ID
5724J0800
Reported release
700
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2010-09-01
Closed date
2010-09-28
Last modified date
2010-10-01

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 APP S
Fixed component ID
5724J0800

Applicable component levels

R700 PSY
UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
24 October 2021

Tips

PM21702: IBM StAX Parser might hang while parsing a large XML document.

Fixes are available

Subscribe

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

R700 PSY

Document Information

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