diff --git a/core/java/android/os/SystemVibrator.java b/core/java/android/os/SystemVibrator.java
index d0d6cb76280a6..003776175f266 100644
--- a/core/java/android/os/SystemVibrator.java
+++ b/core/java/android/os/SystemVibrator.java
@@ -396,7 +396,7 @@ public class SystemVibrator extends Vibrator {
             mExecutor.execute(() -> {
                 boolean anyVibrating;
                 synchronized (mLock) {
-                    int allInitializedMask = 1 << mVibratorListeners.size() - 1;
+                    int allInitializedMask = (1 << mVibratorListeners.size()) - 1;
                     int vibratorMask = 1 << vibratorIdx;
                     if ((mInitializedMask & vibratorMask) == 0) {
                         // First state report for this vibrator, set vibrating initial value.