Okay, to allow for me to make forward progress here I've decided to
follow the "principle of least brokenness" ;-)
Recap: Because of JVMTI event callbacks it is possible for a thread to
set its current pending monitor as a JvmtiRawMonitor when it was already
set for an ObjectMonitor. This is broken in at least two ways:
- when the raw monitor use completes the pending monitor is set to NULL,
not restored to the ObjectMonitor
- whilst the raw monitor is seen as the pending monitor the
ObjectMonitor is not considered by the deadlock detection logic
Ignoring what I'm currently doing with jvmtiRawMonitor, I do not know
how to fix the above brokenness and it is out of scope for what I am
trying to do.
So what I propose is to make things no more broken than they are now,
and actually improve things a little:
- the pending JvmtiRawMonitor is given preference over the ObjectMonitor
in the deadlock detection code (this emulates current situation of the
raw monitor overwriting the pending ObjectMonitor)
- we no longer lose the fact we were also pending on an ObjectMonitor
- the stack printing code in the deadlock detector prints information
about both the raw monitor and the ObjectMonitor
Updated webrev:
http://cr.openjdk.java.net/~dholmes/8231289/webrev.v2/
The only change is threadService.cpp
Thanks,
David
