IV19704: CRASH WHEN USING SHARED CLASSES

APAR status

• Closed as program error.

Error description

• Error Message: Crash when using shared classes
  .
  Stack Trace: Javacore stack trace of failing thread:
  1XMCURTHDINFO  Current thread
  NULL           ----------------------
  3XMTHREADINFO      "Default Executor-thread-0"
  J9VMThread:0x08BA4300, j9thread_t:0x00E4EF98,
  java/lang/Thread:0x0F4CA570, state:R, prio=5
  3XMTHREADINFO1            (native thread ID:0x1844, native
  priority:0x5, native policy:UNKNOWN)
  3XMTHREADINFO3           Java callstack:
  4XESTACKTRACE                at
  com/ibm/oti/shared/SharedClassURLHelperImpl.findSharedClassImpl3
  (Native Method)
  4XESTACKTRACE                at
  com/ibm/oti/shared/SharedClassURLHelperImpl.findSharedClass(Shar
  edClassURLHelperImpl.java:78(Compiled Code))
  5XESTACKTRACE                   (entered lock:
  com/ibm/oti/shared/SharedClassURLHelperImpl@0x10640AA0, entry
  count: 1)
  4XESTACKTRACE                at
  com/ibm/oti/shared/SharedClassURLHelperImpl.findSharedClass(Shar
  edClassURLHelperImpl.java:43(Compiled Code))
  4XESTACKTRACE                at
  com/ibm/cds/CDSBundleFile.getClassBytes(CDSBundleFile.java:207(C
  ompiled Code))
  4XESTACKTRACE                at
  com/ibm/cds/CDSBundleFile.getEntry(CDSBundleFile.java:90(Compile
  d Code))
  ...snip...
  3XMTHREADINFO3           Native callstack:
  4XENATIVESTACK
  Java_com_ibm_oti_shared_SharedClassURLHelperImpl_findSharedClass
  Impl3+0xd7 (shared.c:1184, 0x68039787
  <OSB>jclscar_26+0x29787<CSB>)
  ...snip...
  .
  

Local fix

• Issue can be worked around by disabling shared classes using
  -Xshareclasses:none.
  

Problem summary

• The shared classes code was accessing a garbage-collected
  ClassLoader and crashing when null was passed to one of the
  native methods.
  

Problem conclusion

• This defect will be fixed in:
  6.0.1 SR2
  7.0.0 SR1
  6.0.0 SR11
  .
  The shared classes code has been updated to check for
  garbage-collected ClassLoaders before every access and handle
  this condition internally, or throw an exception if the use is
  in error.
  

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

  J9 COMMON CODE

• Fixed component ID

  620700127

Applicable component levels

• R260 PSY

     UP

• R600 PSY

     UP