PI71844: Deadlock in ICU library - ICUResourceBundle.instantiateBundle

7.0.0.43: WebSphere Application Server V7.0 Fix Pack 43
7.0.0.45: WebSphere Application Server V7.0 Fix Pack 45
7.0.0.45: Java SDK 1.6 SR16 FP60 Cumulative Fix for WebSphere Application Server
7.0.0.43: Java SDK 1.6 SR16 FP41 Cumulative Fix for WebSphere Application Server

APAR status

• Closed as program error.

Error description

• A hang condition may occur due to a deadlock between two classes
  
     com/ibm/icu/impl/ICUResourceBundle
  and
     com/ibm/icu/util/UResourceBundle
  
  
  This deadlock is caused by misplaced synchronization on the
  static method ICUResourceBundle.instantiateBundle().  The
  synchronization is to protect a static resource in its
  superclass UResourceBundle. UResourceBundle uses static
  synchronized methods to protect the resource.
  
  So the problem is the "synchronized" keyword on the static
  method in the subclass ( ICUResourceBundle.instantiateBundle()
  ) is actually a different lock for the same resource.  It locks
  on ICUResourceBundle.class.  It needs to use the same lock as
  the superclass.
  
  The result is the deadlock:
  
  Thread A - holds lock ICUResourceBundle.class
           - needs lock UResourceBundle.class
  
  Thread B - holds lock UResourceBundle.class
           - needs lock ICUResourceBundle.class
  
  The fix is to remove the "synchronized" on the
  ICUResourceBundle.instantiateBundle() method, and then enclose
  the contents of that method inside a sync block like this:
  
  protected static ... instantiateBundle( ... ) {
      synchronized(UResourceBundle.class) {
         ...
      }
  }
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server V7                                   *
  ****************************************************************
  * PROBLEM DESCRIPTION: A thread synchronization problem in     *
  *                      International Components for            *
  *                      Unicode (ICU) library might cause the   *
  *                      application to hang.                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The International Components for Unicode (ICU) for java
  library (version 3.4.5) is included with WebSphere Application
  Server.
  Incorrect coding for synchronization on the static method
  ICUResourceBundle.instantiateBundle() might cause a hang
  condition.  The problem can be diagnosed by taking java core
  dumps.
  The dumps will show a deadlock between two threads, similar to
  the following:
  Dump Event "user" (00004000) received
  Deadlock detected !!!
  ----------
  Thread "WebContainer : 3" (0x0000000003B55200)
  is waiting for:
  com/ibm/icu/impl/ICUResourceBundle@0x0000000012796398/0x00000000
  127963A4:
  which is owned by:
  Thread "WebContainer : 10" (0x00000000041C0500)
  which is waiting for:
  com/ibm/icu/util/UResourceBundle@0x0000000012796370/0x0000000012
  79637C:
  which is owned by:
  Thread "WebContainer : 3" (0x0000000003B55200)
  ----------
  "WebContainer : 3" J9VMThread:0x0000000003B55200,
  Java callstack:
  at
  com/ibm/icu/impl/ICUResourceBundle.getBundleInstance(ICUResource
  Bundle.java:1140)
  at
  com/ibm/icu/util/UResourceBundle.instantiateBundle(UResourceBund
  le.java:498)
  at
  com/ibm/icu/util/UResourceBundle.getBundleInstance(UResourceBund
  le.java:127)
  at
  com/ibm/icu/util/UResourceBundle.getBundleInstance(UResourceBund
  le.java:108)
  at
  com/ibm/icu/util/UResourceBundle.getBundleInstance(UResourceBund
  le.java:195)
  at
  com/ibm/icu/text/RuleBasedCollator.<init>(RuleBasedCollator.java
  :1811)
  at
  com/ibm/icu/text/CollatorServiceShim$CService$1CollatorFactory.h
  andleCreate(CollatorServiceShim.java:114)
  at
  com/ibm/icu/impl/ICULocaleService$LocaleKeyFactory.create(ICULoc
  aleService.java:364)
  at
  com/ibm/icu/impl/ICUService.getKey(ICUService.java:463)
  at
  com/ibm/icu/impl/ICUService.getKey(ICUService.java:383)
  at
  com/ibm/icu/impl/ICULocaleService.get(ICULocaleService.java:72)
  at
  com/ibm/icu/impl/ICULocaleService.get(ICULocaleService.java:56)
  at
  com/ibm/icu/text/CollatorServiceShim.getInstance(CollatorService
  Shim.java:34)
  at
  com/ibm/icu/text/Collator.getInstance(Collator.java:484)
  at
  com/ibm/icu/text/Collator.getInstance(Collator.java:501)
  at
  com/ibm/commerce/bi/taglib/BaseTag.doStartTag(BaseTag.java:93)
  ----------
  "WebContainer : 10" J9VMThread:0x00000000041C0500,
  Java callstack:
  at
  com/ibm/icu/impl/ICUResourceBundle.instantiateBundle(ICUResource
  Bundle.java:1155)
  at
  com/ibm/icu/impl/ICUResourceBundle.getBundleInstance(ICUResource
  Bundle.java:1140)
  at
  com/ibm/icu/impl/ICUResourceBundleImpl.findResource(ICUResourceB
  undleImpl.java:706)
  at
  com/ibm/icu/impl/ICUResourceBundleImpl.createBundleObject(ICURes
  ourceBundleImpl.java:195)
  at
  com/ibm/icu/impl/ICUResourceBundleImpl.access$1300(ICUResourceBu
  ndleImpl.java:29)
  at
  com/ibm/icu/impl/ICUResourceBundleImpl$ResourceTable.handleGet(I
  CUResourceBundleImpl.java:269)
  at
  com/ibm/icu/impl/ICUResourceBundleImpl$ResourceTable.handleGet(I
  CUResourceBundleImpl.java:246)
  at
  com/ibm/icu/impl/ICUResourceBundle.findResourceWithFallback(ICUR
  esourceBundle.java:1105)
  at
  com/ibm/icu/impl/ICUResourceBundle.getWithFallback(ICUResourceBu
  ndle.java:652)
  at
  com/ibm/icu/text/RuleBasedCollator.<init>(RuleBasedCollator.java
  :1824)
  at
  com/ibm/icu/text/CollatorServiceShim$CService$1CollatorFactory.h
  andleCreate(CollatorServiceShim.java:114)
  at
  com/ibm/icu/impl/ICULocaleService$LocaleKeyFactory.create(ICULoc
  aleService.java:364)
  at
  com/ibm/icu/impl/ICUService.getKey(ICUService.java:463)
  at
  com/ibm/icu/impl/ICUService.getKey(ICUService.java:383)
  at
  com/ibm/icu/impl/ICULocaleService.get(ICULocaleService.java:72)
  at
  com/ibm/icu/impl/ICULocaleService.get(ICULocaleService.java:56)
  at
  com/ibm/icu/text/CollatorServiceShim.getInstance(CollatorService
  Shim.java:34)
  at
  com/ibm/icu/text/Collator.getInstance(Collator.java:484)
  at
  com/ibm/icu/text/Collator.getInstance(Collator.java:501)
  at
  com/ibm/commerce/bi/taglib/BaseTag.doStartTag(BaseTag.java:93)
  ----------
  The problem is the static method
  ICUResourceBundle.instantiateBundle() is synchronized using
  the wrong lock.  It should be using the same lock as its
  superclass.
  

Problem conclusion

• The static method ICUResourceBundle.instantiateBundle() has
  been updated to use the same lock as its superclass.
  
  The fix for this APAR is currently targeted for inclusion in
  fix pack 7.0.0.43.  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 is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WEBS APP SERV N

• Fixed component ID

  5724H8800

Applicable component levels

• R700 PSY

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