RFR: 8195979: [Graal] crash in src/hotspot/share/runtime/mutex.cpp:1341 when Graal JIT is used

[Kim Barrett]

> On Jan 24, 2018, at 2:52 PM, Kim Barrett <kim.barrett at oracle.com> wrote:
> 
> Please review this workaround for a lock rank ordering issue. When
> using Graal, JNI references are released while holding the
> Patching_lock (a rank=special lock).
> 
> […]
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8195979
> 
> Webrev:
> http://cr.openjdk.java.net/~kbarrett/8195979/open.00/
> 
> Testing:
> Mach5 hs-tier{1-5}, jdk-tier{1-3}
> Local testing of Ekaterina's reproducer in CR. 

The change is small, has been run through lots of tests, and I have
several reviewers (and Reviewers). Given those positives, and that the
bug is a P2 integration blocker and blocking some other testing, I'm
going to ignore the 24 hour rule and go ahead and push.