APAR status
Closed as program error.
Error description
Error Message: Segmentation Fault in libj9dyn26.so or java.lang.ClassFormatError exception . Stack Trace: j9bcutil_readClassFileBytes () from jre/lib/ppc/default/libj9dyn26.so lassFileParser::parseClassFile () from jre/lib/ppc/default/libj9dyn26.so ROMClassBuilder::buildROMClass () from jre/lib/ppc/default/libj9dyn26.so j9bcutil_buildRomClass () from jre/lib/ppc/default/libj9dyn26.so callDynamicLoader () from jre/lib/ppc/default/libj9dyn26.so internalLoadROMClass () from jre/lib/ppc/default/libj9dyn26.so reloadROMClasses () from jre/lib/ppc/default/libj9jvmti26.so redefineClassesCommon () from jre/lib/ppc/default/libj9jvmti26.so jvmtiRetransformClasses () from jre/lib/ppc/default/libj9jvmti26.so retransformClasses () from jre/lib/ppc/libinstrument.so Java_sun_instrument_InstrumentationImpl_retransformClasses0 () from jre/lib/ppc/libinstrument.so .
Local fix
This problem can be prevented by disabling the shared class cache using -Xshareclasses:none. It can also be worked around by removing the re-transformation capable JVMTI agent.
Problem summary
Problem is seen when the same shared class cache is used by multiple JVMs. In certain situations a JVM may store a re-transformed class in the shared cache such that one of the pointers in the class refers to the JVM's private memory. When another JVM tries to access this pointer, it may suffer a java.lang.ClassFormatError or a segmentation fault if that memory is not mapped in its address space.
Problem conclusion
This defect will be fixed in: 7.0.0 SR1 6.0.1 SR2 . The JVM has been updated to prevent the pointer in the shared cache class from referring to memory outside the cache.
Temporary fix
Comments
APAR Information
APAR number
IV19701
Reported component name
J9 COMMON CODE
Reported component ID
620700127
Reported release
260
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2012-04-13
Closed date
2012-04-13
Last modified date
2012-04-13
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
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Document Information
Modified date:
21 February 2022