RFA: 8208091: SA: jhsdb jstack --mixed throws UnmappedAddressException on i686

[Severin Gehwolf]

Hi,

Please approve this 8u packport of JDK-8208091. In JDK 12 the command
to trigger the bug is "jhsdb jstack --mixed". In JDK 8u the command is
"jstack -m". The bug is the same, though. The actual fix is the same as
in JDK 12 post path-unshuffeling.

The testing infrastructure is rather different in JDK 8. There are
hardly any serviceability tests. In order to keep changes to a stable
release minimal the JDK 8u patch only inludes the fix. The test isn't
100% guaranteed to trigger the problem anyway. Thoughts?

Bug: https://bugs.openjdk.java.net/browse/JDK-8208091
JDK 8 patch: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8208091/JDK-8208091.jdk8.export.patch
JDK 12 change: http://hg.openjdk.java.net/jdk/jdk/rev/2e98c7737d8f

Thanks,
Severin

Prior the fix:

# ./jdk-8u-prior-jstack-fix/bin/jstack -m 2339
Attaching to process ID 2339, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.71-b00
Deadlock Detection:

No deadlocks found.

----------------- 2340 -----------------
0xf7755430		????????
----------------- 2341 -----------------
0xf7755430		????????
----------------- 2342 -----------------
0xf7755430		????????
----------------- 2343 -----------------
0xf7755430		????????
----------------- 2344 -----------------
0xf7755430		????????
----------------- 2345 -----------------
0xf7755430		????????
----------------- 2346 -----------------
0xf7755430		????????
----------------- 2347 -----------------
0xf7755430		????????
sun.jvm.hotspot.debugger.UnmappedAddressException: f0
	at sun.jvm.hotspot.debugger.PageCache.checkPage(PageCache.java:208)
	at sun.jvm.hotspot.debugger.PageCache.getData(PageCache.java:63)
	at sun.jvm.hotspot.debugger.DebuggerBase.readBytes(DebuggerBase.java:225)
	at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.readCInteger(LinuxDebuggerLocal.java:498)
	at sun.jvm.hotspot.debugger.DebuggerBase.readAddressValue(DebuggerBase.java:462)
	at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.readAddress(LinuxDebuggerLocal.java:433)
	at sun.jvm.hotspot.debugger.linux.LinuxAddress.getAddressAt(LinuxAddress.java:74)
	at sun.jvm.hotspot.debugger.linux.x86.LinuxX86CFrame.sender(LinuxX86CFrame.java:69)
	at sun.jvm.hotspot.tools.PStack.run(PStack.java:161)
	at sun.jvm.hotspot.tools.PStack.run(PStack.java:58)
	at sun.jvm.hotspot.tools.PStack.run(PStack.java:53)
	at sun.jvm.hotspot.tools.JStack.run(JStack.java:66)
	at sun.jvm.hotspot.tools.Tool.startInternal(Tool.java:260)
	at sun.jvm.hotspot.tools.Tool.start(Tool.java:223)
	at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118)
	at sun.jvm.hotspot.tools.JStack.main(JStack.java:92)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sun.tools.jstack.JStack.runJStackTool(JStack.java:140)
	at sun.tools.jstack.JStack.main(JStack.java:106)
----------------- 2348 -----------------
0xf7755430		????????
----------------- 2349 -----------------
0xf7755430		????????
----------------- 2350 -----------------
0xf7755430		????????
----------------- 2351 -----------------
0xf7755430		????????
----------------- 2339 -----------------
0xf7755430		????????

Post fix:

$ ./jdk-8u-post-jstack-fix/bin/jstack -m 2339
Attaching to process ID 2339, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.71-b00
Deadlock Detection:

No deadlocks found.

----------------- 2340 -----------------
0xf7755430		????????
----------------- 2341 -----------------
0xf7755430		????????
----------------- 2342 -----------------
0xf7755430		????????
----------------- 2343 -----------------
0xf7755430		????????
----------------- 2344 -----------------
0xf7755430		????????
----------------- 2345 -----------------
0xf7755430		????????
----------------- 2346 -----------------
0xf7755430		????????
----------------- 2347 -----------------
0xf7755430		????????
----------------- 2348 -----------------
0xf7755430		????????
----------------- 2349 -----------------
0xf7755430		????????
----------------- 2350 -----------------
0xf7755430		????????
----------------- 2351 -----------------
0xf7755430		????????
----------------- 2339 -----------------
0xf7755430		????????