IV26904: JVM CRASHES WHEN OPENING NON-PERSISTENT SHARED CLASS CACHE IN RE AD-ONLY MODE WITH A MEMORY CONTROL FILE OF 0 SIZE

APAR status

• Closed as program error.

Error description

• Error Message: Segmentation error occurs when a user tries to
  use a non-persistent shared class cache in read-only mode with a
  memory control file of 0 size.
  .
  Stack Trace: j9shsem_deprecated_getid at
  sysvipc/j9shsem_deprecated.c:1173
  SH_OSCachesysv::initializeHeader at OSCachesysv.cpp:577
  SH_OSCachesysv::openCache at OSCachesysv.cpp:348
  SH_OSCachesysv::startup at OSCachesysv.cpp:224
  SH_CompositeCacheImpl::startup at CompositeCache.cpp:1151
  SH_CacheMap::startup at CacheMap.cpp:425
  j9shr_init at shrinit.cpp:2837
  J9VMDllMain at shrclssup.c:225
  runJ9VMDllMain at jvminit.c:2310
  pool_do at pool.c:636
  runInitializationStage at jvminit.c:2260
  protectedInitializeJavaVM at jvminit.c:5051
  j9sig_protect at jvminit.c:948
  JNI_CreateJavaVM at jniinv.c:101
  JNI_CreateJavaVM at jvm.c:2089
  JNI_CreateJavaVM () from
  /team/ashu/java7sr1/unzipped/jre/lib/amd64/j9vm/libjvm.so
  JavaMain () from
  /team/ashu/java7sr1/unzipped/jre/bin/../lib/amd64/jli/libjli.so
  .
  

Local fix

• Remove the control files by using -Xshareclasses:destroy option
  and retry.
  

Problem summary

• The problem occurs when the memory control file of a
  non-persistent shared class cache is of 0 size.
  Using such a cache in read-only mode specified by
  -Xsharedclasses:readonly option results in JVM to crash.
  

Problem conclusion

• This defect will be fixed in:
  6.0.1 SR3
  7.0.0 SR2
  .
  JVM has been fixed to display a proper error message when it
  tries to attach to a non-persistent shared class cache with
  memory control file of size 0 bytes in read-only mode.
  

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

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