8325754: Dead AbstractQueuedSynchronizer$ConditionNodes survive minor…

… garbage collections Backport-of: 60cbf2925024b1c2253256688ae41741fff0a860
openjdk · Jun 24, 2024 · 241b054 · 241b054 · openjdk-notifier · Jun 24, 2024
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commit 241b054
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diff --git a/src/java.base/share/classes/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.java b/src/java.base/share/classes/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.java
@@ -1127,13 +1127,18 @@ public ConditionObject() { }
         private void doSignal(ConditionNode first, boolean all) {
             while (first != null) {
                 ConditionNode next = first.nextWaiter;
+
                 if ((firstWaiter = next) == null)
                     lastWaiter = null;
+                else
+                    first.nextWaiter = null; // GC assistance
+
                 if ((first.getAndUnsetStatus(COND) & COND) != 0) {
                     enqueue(first);
                     if (!all)
                         break;
                 }
+
                 first = next;
             }
         }

diff --git a/src/java.base/share/classes/java/util/concurrent/locks/AbstractQueuedSynchronizer.java b/src/java.base/share/classes/java/util/concurrent/locks/AbstractQueuedSynchronizer.java
@@ -1506,13 +1506,18 @@ public ConditionObject() { }
         private void doSignal(ConditionNode first, boolean all) {
             while (first != null) {
                 ConditionNode next = first.nextWaiter;
+
                 if ((firstWaiter = next) == null)
                     lastWaiter = null;
+                else
+                    first.nextWaiter = null; // GC assistance
+
                 if ((first.getAndUnsetStatus(COND) & COND) != 0) {
                     enqueue(first);
                     if (!all)
                         break;
                 }
+
                 first = next;
             }
         }