[GR-20089] Always use condLock.lock() for locking the ConditionVariable's ReentrantLock

* Changing the thread status or consuming interrupt as before was incorrect
  and could lead to an interrupt from Thread#{run,wakeup} being missed.
* condLock is only held for a short number of non-blocking instructions,
  so there is no need to poll for safepoints while locking it.

Author: eregon

src/main/java/org/truffleruby/core/mutex/ConditionVariableNodes.java

@@ -22,7 +22,6 @@
 import org.truffleruby.builtins.PrimitiveArrayArgumentsNode;
 import org.truffleruby.core.thread.GetCurrentRubyThreadNode;
 import org.truffleruby.core.thread.ThreadManager;
-import org.truffleruby.core.thread.ThreadManager.BlockingAction;
 import org.truffleruby.core.thread.ThreadStatus;
 import org.truffleruby.language.Visibility;
 import org.truffleruby.language.objects.AllocateObjectNode;
@@ -44,8 +43,12 @@ public abstract static class AllocateNode extends CoreMethodArrayArgumentsNode {
 
         @Specialization
         protected DynamicObject allocate(DynamicObject rubyClass) {
-            ReentrantLock lock = new ReentrantLock();
-            return allocateNode.allocate(rubyClass, lock, lock.newCondition(), 0, 0);
+            // condLock is only held for a short number of non-blocking instructions,
+            // so there is no need to poll for safepoints while locking it.
+            // It is an internal lock and so locking should be done with condLock.lock()
+            // to avoid changing the Ruby Thread status and consume Java thread interrupts.
+            final ReentrantLock condLock = new ReentrantLock();
+            return allocateNode.allocate(rubyClass, condLock, condLock.newCondition(), 0, 0);
         }
 
     }
@@ -95,11 +98,11 @@ private void waitInternal(DynamicObject conditionVariable, ReentrantLock mutexLo
             // it should only be considered if we are inside Mutex#sleep when Thread#{run,wakeup} is called.
             Layouts.THREAD.getWakeUp(thread).set(false);
 
-            // condLock must be locked before unlocking mutexLock, to avoid losing potential signals
-            getContext().getThreadManager().runUntilResult(this, () -> {
-                condLock.lockInterruptibly();
-                return BlockingAction.SUCCESS;
-            });
+            // condLock must be locked before unlocking mutexLock, to avoid losing potential signals.
+            // We must not change the Ruby Thread status and not consume a Java thread interrupt while locking condLock.
+            // If there is an interrupt, it should be consumed by condition.await() and the Ruby Thread sleep status
+            // must imply being ready to be interrupted by Thread#{run,wakeup}.
+            condLock.lock();
             mutexLock.unlock();
 
             Layouts.CONDITION_VARIABLE
@@ -205,13 +208,7 @@ protected DynamicObject signal(DynamicObject self) {
             final ReentrantLock condLock = Layouts.CONDITION_VARIABLE.getLock(self);
             final Condition condition = Layouts.CONDITION_VARIABLE.getCondition(self);
 
-            if (!condLock.tryLock()) {
-                getContext().getThreadManager().runUntilResult(this, () -> {
-                    condLock.lockInterruptibly();
-                    return BlockingAction.SUCCESS;
-                });
-            }
-
+            condLock.lock();
             try {
                 if (Layouts.CONDITION_VARIABLE.getWaiters(self) > 0) {
                     Layouts.CONDITION_VARIABLE.setSignals(self, Layouts.CONDITION_VARIABLE.getSignals(self) + 1);
@@ -234,13 +231,7 @@ protected DynamicObject broadcast(DynamicObject self) {
             final ReentrantLock condLock = Layouts.CONDITION_VARIABLE.getLock(self);
             final Condition condition = Layouts.CONDITION_VARIABLE.getCondition(self);
 
-            if (!condLock.tryLock()) {
-                getContext().getThreadManager().runUntilResult(this, () -> {
-                    condLock.lockInterruptibly();
-                    return BlockingAction.SUCCESS;
-                });
-            }
-
+            condLock.lock();
             try {
                 if (Layouts.CONDITION_VARIABLE.getWaiters(self) > 0) {
                     Layouts.CONDITION_VARIABLE.setSignals(