APAR status
Closed as program error.
Error description
Error Message: The JVM crashes while executing a JIT-compiled Java method that seemingly contains an invalid instruction, or takes a wild branch to an unrelated method or invalid memory. The invalid instruction typically has been partially overwritten with the nibble 0xF. If verbose JIT logging is turned on, the crashing method may be shown with a code cache address range that overlaps that of another method, e.g. + (warm) Testcase.foo()V @ 0x52CF4AFC-0x52CF4B20/0x52D62F8C-0x52D63F6C Q_SZ=11 sync compThread=1 + (profiled hot) Testcase.foo()V @ 0x52D0B3FC-0x52D0CD58/0x52D59F7C-0x52D5A7B4 7.01% T Q_SZ=11 sync compThread=1 + (warm) Testcase.bar()V @ 0x52D1FCF4-0x52D1FF30/0x52D6328C-0x52D6349C Q_SZ=7 sync compThread=0 In this example, the code cache address range of Testcase.bar (0x52D6328C to 0x52D6349C) overlaps that of the first version of Testcase.foo (0x52D62F8C to 0x52D63F6C), which has just been re-compiled at a higher optimization level. Stack Trace: N/A This problem only occurs on System z when certain JVMTI agents are in use.
Local fix
Detaching all JVMTI agents will work around this issue.
Problem summary
The problem can only occur when HCR mode is enabled by JVMTI agents. When a method is re-compiled, the JIT code cache space occupied by its old version is freed, along with any associated run-time assumption data. However, in some situations with HCR enabled, the run-time assumption data is not freed, causing corruption in the JIT code cache later on.
Problem conclusion
This defect will be fixed in: 6.0.0 SR11 6.0.1 SR3 7.0.0 SR2 . The JIT compiler has been updated to ensure that proper assumptions get freed in the scenarios identified.
Temporary fix
Comments
APAR Information
APAR number
IV20650
Reported component name
JIT
Reported component ID
620700124
Reported release
600
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2012-05-04
Closed date
2012-05-04
Last modified date
2013-03-30
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
JIT
Fixed component ID
620700124
Applicable component levels
R600 PSY
UP
R260 PSY
UP
[{"Business Unit":{"code":"BU048","label":"IBM Software"},"Product":{"code":"SSC9HBA","label":"Just In Time (JIT) Compiler"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"6.0","Edition":"","Line of Business":{"code":"","label":""}}]
Document Information
Modified date:
30 March 2013