diff --git a/src/java.base/share/classes/java/lang/Thread.java b/src/java.base/share/classes/java/lang/Thread.java
index 19c3cda11c6..aa6e1db54ca 100644
--- a/src/java.base/share/classes/java/lang/Thread.java
+++ b/src/java.base/share/classes/java/lang/Thread.java
@@ -1774,7 +1774,9 @@ public static boolean interrupted() {
     public boolean isInterrupted() {
         // use fully qualified name to avoid ambiguous class error
         if (com.ibm.oti.vm.VM.isJVMInSingleThreadedMode()) {
-            return isInterruptedImpl();
+            synchronized (interruptLock) {
+                return isInterruptedImpl();
+            }
         }
         return interrupted;
     }
@@ -3031,7 +3033,9 @@ private void setPriority0(int newPriority) {
     }
 
     private void interrupt0() {
-        interruptImpl();
+        synchronized (interruptLock) {
+            interruptImpl();
+        }
     }
 
     private static void clearInterruptEvent() {