IV26012: SEGMENTATION ERROR DURING JIT COMPILATION ON 32-BIT

APAR status

• Closed as program error.

Error description

• Error Message: There are a number of possible error messages,
  but what they have in common is:
  - vmState begins with 0x0005
  - There is a "Method_being_compiled"
  - InaccessibleAddress starts with a series of "F"s.
  Here is an example:
  Unhandled exception
  Type=Segmentation error vmState=0x00051dff
  J9Generic_Signal_Number=00000004 Signal_Number=0000000b
  Error_Value=00000000 Signal_Code=00000001
  Handler1=559A570A Handler2=55A37AB7 InaccessibleAddress=FFFF5000
  EDI=FFFF5000 ESI=0000EBBC EAX=00000000 EBX=5639C944
  ECX=000036DC EDX=00000000
  EIP=55653327 ES=002B DS=002B ESP=D943B988
  EFlags=00010246 CS=0023 SS=002B EBP=D943BA68
  Module=/lib/libc.so.6
  Module_base_address=555DC000 Symbol=memset
  Symbol_address=556532F0
  Method_being_compiled=com/ibm/jtc/svt/tests/invoke/AsTypeTest.te
  stConvertInt(I)V
  Target=2_60_20110805_088344 (Linux 2.6.32.36-0.5-default)
  CPU=x86 (8 logical CPUs) (0x3ed34c000 RAM)
  .
  Stack Trace: N/A
  .
  

Local fix

• 64-bit builds are far less likely to exhibit this problem, so if
  switching to 64-bit is a viable option, that is very likely
  (almost certain) to make the problem disappear.
  

Problem summary

• The JIT's internal memory allocator doesn't properly handle the
  situation where the address of allocated memory is right at the
  top of the address space.  In that case, if an allocation
  request is too large to accommodate, the calculations will
  overflow, causing invalid pointers to be generated.
  

Problem conclusion

• This defect will be fixed in:
  6.0.0 SR11
  5.0.0 SR14
  .
  The JIT has been fixed to avoid overflow in the memory
  allocation calculations.
  

Temporary fix

Comments

APAR Information

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

  IV26011

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

Fix information

• Fixed component name

  JAVA 5 JIT

• Fixed component ID

  620500124

Applicable component levels

• R500 PSY

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