src/java.base/share/classes/jdk/internal/misc/Blocker.java

*** 65,10 ***
--- 65,11 ---
       * Marks the beginning of a possibly blocking operation.
       * @return the return value from the attempt to compensate or -1 if not attempted
       */
      public static long begin() {
          if (VM.isBooted()
+                 && Thread.currentThread().isVirtual()
                  && currentCarrierThread() instanceof CarrierThread ct && !ct.inBlocking()) {
              ct.beginBlocking();
              boolean completed = false;
              try {
                  long comp = ForkJoinPools.beginCompensatedBlock(ct.getPool());