RFR: 8344935: [ubsan]: javaThread.hpp:1241:52: runtime error: load of value 9831830, which is not a valid value for type 'freeze_result'

[David Holmes]

On Mon, 25 Nov 2024 13:56:20 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

> Seems we miss initialization of  _last_freeze_fail_result in the  JavaThread constructor, this should be added.
> Causes otherwise ubsan issues in the test  java/lang/Thread/virtual/MonitorEnterExit.java#Xcomp-TieredStopAtLevel1-LM_LEGACY 
> 
> /priv/jenkins/client-home/workspace/openjdk-jdk-weekly-linux_x86_64-opt/jdk/src/hotspot/share/runtime/javaThread.hpp:1241:52: runtime error: load of value 9831830, which is not a valid value for type 'freeze_result'
>     #0 0x7f5edef378eb in JavaThread::last_freeze_fail_result() src/hotspot/share/runtime/javaThread.hpp:1241
>     #1 0x7f5edef378eb in JVM_VirtualThreadPinnedEvent src/hotspot/share/prims/jvm.cpp:3805

The missing initializer is fine but note that as @reinrich stated in the JBS issue there is actually a bug here as we should have already set a reason if we are calling  `JVM_VirtualThreadPinnedEvent`. With your change we should now get an assertion failure.

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PR Review: https://git.openjdk.org/jdk/pull/22361#pullrequestreview-2459613005