Hi David,

The fix looks good to me.
Thank you for taking care about it!

Thanks,
Serguei


On 1/24/19 6:46 PM, David Holmes wrote:
Bug: https://bugs.openjdk.java.net/browse/JDK-8217618
webrev: http://cr.openjdk.java.net/~dholmes/8217618/webrev/

Lots of analysis in the bug report. Bottom line: SuspendThread of the current thread was not actually suspending the thread until it hit specific thread-state transitions. That meant that SuspendThread would actually return and continue executing native code whilst suspended, in violation of the specification for it.

The fix is quite simple: in java_suspend() we check for the current thread and call java_suspend_self().

Testing:
 - Any test that looked like it referred to thread suspension
  - hotspot/jtreg/vmTestbase/nsk/jvmti/*
  - jdk/
     com/sun/jdi/*
     java/lang/ThreadGroup/Suspend.java
java/lang/management/CompositeData/ThreadInfoCompositeData.java
     java/lang/management/ThreadMXBean/*
     java/nio/channels/SocketChannel/SendUrgentData.java
java/util/logging/LogManager/Configuration/TestConfigurationLock.java

 - Mach 5 tiers 1-3 (in progress)

Two tests were found to be erroneously relying on SuspendThread returning whilst suspended:

- vmTestbase/nsk/jvmti/scenarios/sampling/SP05/sp05t003/sp05t003.cpp

The test updated a shared counter after the SuspendThread call, but it needed to be updated before the call.

- vmTestbase/nsk/jvmti/scenarios/hotswap/HS202/hs202t002/hs202t002.cpp

The test was using a 0 return value from SuspendThread as an indicator that the thread was in the suspended state - but that value can't be seen until after SuspendThread returns, which is after the thread is resumed. So I ripped out the custom state tracking logic and replaced with a simple check of GetThreadState.

Thanks,
David

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