APAR status
Closed as program error.
Error description
Error Message: N/A . Stack Trace: N/A .
Local fix
N/A
Problem summary
When JVM adds data to shared class cache, it marks the pages read-only when the whole page is filled with data. Partially filled pages thus remain write-able unless they are completely filled up, and may be corrupted.
Problem conclusion
JVM has been updated to memory protect partially filled pages in the shared class cache. By default (that is when -Xshareclasses:mprotect is not specified or -Xshareclasses:mprotect=default is specified) after JVM startup phase is over, whenever new data is to be added to the shared class cache, JVM first changes the memory protection of any partially filled pages to read-write, adds data to the cache, and then changes the memory protection of any partially filled pages to read-only. To provide more control on memory protection of partially filled pages, following -Xshareclasses options have been added: -Xshareclasses:mprotect=onfind This option protects partially filled pages when JVM reads new data in the cache added by other JVM. -Xshareclasses:mprotect=nopartialpages This option disables memory protection of partially filled pages. JVM would protect only those pages which are completely full. (Previous default) -Xshareclasses:mprotect=partialpagesonstartup By default JVM performs memory protection of partially filled pages after startup phase is over. This option enables memory protection of partially filled pages since JVM startup. These change are applicable to Linux and Windows operating system only. . This APAR will be fixed in the following Java Releases: 8 SR2 FP10 (8.0.2.10) 7 SR9 FP30 (7.0.9.30) 6 R1 SR8 FP20 (6.1.8.20) 7 R1 SR3 FP30 (7.1.3.30) . Contact your IBM Product's Service Team for these Service Refreshes and Fix Packs. For those running stand-alone, information about the available Service Refreshes and Fix Packs can be found at: https://www.ibm.com/developerworks/java/jdk/
Temporary fix
Comments
APAR Information
APAR number
IV78991
Reported component name
J9 COMMON CODE
Reported component ID
620700127
Reported release
270
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2015-11-17
Closed date
2015-11-17
Last modified date
2016-01-20
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
R270 PSY
UP
R260 PSY
UP
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Document Information
Modified date:
21 February 2022