IV21492: SEGMENTATION FAULT IN SYSTEM.ARRAYCOPY()

APAR status

• Closed as program error.

Error description

• Error Message: Segmentation fault in System.arraycopy() during
  stress testing when using -Xgcpolicy:metronome or
  -Xgcpolicy:balanced
  .
  Stack Trace: Unhandled exception
  Type=Segmentation error vmState=0x00000000
  J9Generic_Signal_Number=00000004 Signal_Number=0000000b
  Error_Value=00000000 Signal_Code=00000002
  Handler1=4042470A Handler2=404C6AB7 InaccessibleAddress=81070000
  EDI=00000001 ESI=00000800 EAX=8106FFE0 EBX=00002000
  ECX=00000000 EDX=00000004
  EIP=4103AA22 ES=007B DS=007B ESP=092D4B30
  EFlags=00010246 CS=0073 SS=007B EBP=094B6D00
  Module=/jtctest/sdk_installs/pxi3270/pxi3270-20110722_01/ibm-jav
  a-i386-70/jre/lib/i386/default/libjclse7b_26.so
  Module_base_address=41011000 Symbol=java_lang_System_arraycopy
  .
  

Local fix

• If possible switch to the -Xgpolicy:gencon,
  -Xgcpolicy:optthruput or -Xgcpolicy:optavgpause.  Note that
  these GC polices do not provide the same pause time
  characteristics as -Xgcpolicy:metronome or -Xgcpolicy:balanced
  so this work around may cause application issues.
  

Problem summary

• The Segmentation fault was due to a bad calculation if the
  source / destination array ended at the exact end of the heap
  which caused the code to read past the end of the heap memory.
  

Problem conclusion

• This defect will be fixed in:
  7.0.0 SR1
  6.0.1 SR2
  WRT-V3 SR1
  .
  The JVM has been updated to handle this case so that it does not
  read past the end of the heap memory
  

Temporary fix

Comments

APAR Information

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

  IV19458

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

Fix information

• Fixed component name

  WRT VM

• Fixed component ID

  5724R0403

Applicable component levels

• R300 PSY

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