RFR 8193879: Java debugger hangs on method invocation

Daniil Titov daniil.x.titov at oracle.com
Thu Oct 4 04:29:57 UTC 2018

Please review the changes that fix the deadlock in the debugger when the debugger is running with the tracing option on. 

The problem here is that when the tracing is on the "JDI Target VM Interface" thread (the thread that reads all replies and then notifies the thread that sent the request that the reply has been 
received) is waiting for a lock which is already acquired by the thread that sent the request and is waiting for reply.

The fix itself is in src/jdk.jdi/share/classes/com/sun/tools/jdi/VMState.java. 

The patch also reverts the changes done in 8129348 "Debugger hangs in trace mode with TRACE_SENDS" in src/jdk.jdi/share/classes/com/sun/tools/jdi/InvokableTypeImpl.java since they address only a specific case (VM is suspended and static method is invoked) while the proposed fix also solves issue 8129348 as well as issue 8193801 "Debugger hangs in trace mode for non-static methods".

The changes include new tests for issues 8193879, 8193801 and  8129348.

The changes in src/jdk.jdi/share/classes/com/sun/tools/example/debug/tty/TTY.java solve the problem that the prompt is not printed in the debugger output when the breakpoint is hit and the suspend policy is SUSPEND_EVENT_THREAD. This is required for new tests to detect that command "stop thread at ..." is completed.

Mach5 build and jdk_jdi tests succeeded.

Webrev: http://cr.openjdk.java.net/~dtitov/8193879/webrev.01/
Issue: https://bugs.openjdk.java.net/browse/JDK-8193879 


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