RFR(S): 8247533: SA stack walking sometimes fails with sun.jvm.hotspot.debugger.DebuggerException: get_thread_regs failed for a lwp

[Chris Plummer]

Ping. I still need one more review for this. There was one updated 
webev. I list it below so you don't need to dig it up in the long email 
thread:
> I've  updated with webrev based on the new finding that a JavaThread 
> cannot be on the ThreadList after its OS thread has been destroyed 
> since the JavaThread removes itself from the ThreadList, and therefore 
> must be running on its OS thread. The logic of the fix is unchanged 
> from the first webrev, but I updated the comments to better reflect 
> what is going on. I also updated the CR:
>
> https://bugs.openjdk.java.net/browse/JDK-8247533
> http://cr.openjdk.java.net/~cjplummer/8247533/webrev.01/index.html

thanks,

Chris

On 6/17/20 1:34 PM, Chris Plummer wrote:
> Hello,
>
> Please help review the following:
>
> https://bugs.openjdk.java.net/browse/JDK-8247533
> http://cr.openjdk.java.net/~cjplummer/8247533/webrev.00/index.html
>
> The CR contains all the needed details. Here's a summary of changes in 
> each file:
>
> src/jdk.hotspot.agent/linux/native/libsaproc/LinuxDebuggerLocal.cpp
> src/jdk.hotspot.agent/macosx/native/libsaproc/MacosxDebuggerLocal.m
> src/jdk.hotspot.agent/windows/native/libsaproc/sawindbg.cpp
> -Instead of throwing an exception when the OS ThreadID is invalid, 
> print a warning.
>
> src/jdk.hotspot.agent/linux/native/libsaproc/ps_proc.c
> -Improve a print_debug message
>
> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/debugger/bsd/BsdThread.java 
>
> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/debugger/linux/LinuxThread.java 
>
> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/debugger/windbg/amd64/WindbgAMD64Thread.java 
>
> -Deal with the array of registers read in being null due to the OS 
> ThreadID not being valid.
>
> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/debugger/bsd/BsdDebuggerLocal.java 
>
> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/debugger/linux/LinuxDebuggerLocal.java 
>
> -Fix issue with "sun.jvm.hotspot.debugger.DebuggerException" appearing 
> twice when printing the exception.
>
> thanks,
>
> Chris