diff --git a/apex/jobscheduler/service/java/com/android/server/alarm/Alarm.java b/apex/jobscheduler/service/java/com/android/server/alarm/Alarm.java
index 4d646de2e5292a1a6363f14cbe885200aeeff7c7..10764651cdfbd38c00f48c3a5198c879f5255c0c 100644
--- a/apex/jobscheduler/service/java/com/android/server/alarm/Alarm.java
+++ b/apex/jobscheduler/service/java/com/android/server/alarm/Alarm.java
@@ -21,7 +21,7 @@ import static android.app.AlarmManager.ELAPSED_REALTIME_WAKEUP;
 import static android.app.AlarmManager.RTC;
 import static android.app.AlarmManager.RTC_WAKEUP;
 
-import static com.android.server.alarm.AlarmManagerService.clampPositive;
+import static com.android.server.alarm.AlarmManagerService.addClampPositive;
 
 import android.app.AlarmManager;
 import android.app.IAlarmListener;
@@ -146,7 +146,7 @@ class Alarm {
         mPolicyWhenElapsed[REQUESTER_POLICY_INDEX] = requestedWhenElapsed;
         mWhenElapsed = requestedWhenElapsed;
         this.windowLength = windowLength;
-        mMaxWhenElapsed = clampPositive(requestedWhenElapsed + windowLength);
+        mMaxWhenElapsed = addClampPositive(requestedWhenElapsed, windowLength);
         repeatInterval = interval;
         operation = op;
         listener = rec;
@@ -241,8 +241,8 @@ class Alarm {
 
         final long oldMaxWhenElapsed = mMaxWhenElapsed;
         // windowLength should always be >= 0 here.
-        final long maxRequestedElapsed = clampPositive(
-                mPolicyWhenElapsed[REQUESTER_POLICY_INDEX] + windowLength);
+        final long maxRequestedElapsed = addClampPositive(
+                mPolicyWhenElapsed[REQUESTER_POLICY_INDEX], windowLength);
         mMaxWhenElapsed = Math.max(maxRequestedElapsed, mWhenElapsed);
 
         return (oldWhenElapsed != mWhenElapsed) || (oldMaxWhenElapsed != mMaxWhenElapsed);
diff --git a/apex/jobscheduler/service/java/com/android/server/alarm/AlarmManagerService.java b/apex/jobscheduler/service/java/com/android/server/alarm/AlarmManagerService.java
index b96354c396a769cdd62c97e5234fe856c10c33e8..8cc31342ddda65dbd3e6cfb8b69a2dbbc61c4ebd 100644
--- a/apex/jobscheduler/service/java/com/android/server/alarm/AlarmManagerService.java
+++ b/apex/jobscheduler/service/java/com/android/server/alarm/AlarmManagerService.java
@@ -1498,15 +1498,15 @@ public class AlarmManagerService extends SystemService {
         if (futurity < MIN_FUZZABLE_INTERVAL) {
             futurity = 0;
         }
-        long maxElapsed = triggerAtTime + (long) (0.75 * futurity);
+        long maxElapsed = addClampPositive(triggerAtTime, (long) (0.75 * futurity));
         // For non-repeating alarms, window is capped at a maximum of one hour from the requested
         // delivery time. This allows for inexact-while-idle alarms to be slightly more reliable.
         // In practice, the delivery window should generally be much smaller than that
         // when the device is not idling.
         if (interval == 0) {
-            maxElapsed = Math.min(maxElapsed, triggerAtTime + INTERVAL_HOUR);
+            maxElapsed = Math.min(maxElapsed, addClampPositive(triggerAtTime, INTERVAL_HOUR));
         }
-        return clampPositive(maxElapsed);
+        return maxElapsed;
     }
 
     // The RTC clock has moved arbitrarily, so we need to recalculate all the RTC alarm deliveries.
@@ -1593,6 +1593,18 @@ public class AlarmManagerService extends SystemService {
         return (val >= 0) ? val : Long.MAX_VALUE;
     }
 
+    static long addClampPositive(long val1, long val2) {
+        long val = val1 + val2;
+        if (val >= 0) {
+            return val;
+        } else if (val1 >= 0 && val2 >= 0) {
+            /* Both are +ve, so overflow happened. */
+            return Long.MAX_VALUE;
+        } else {
+            return 0;
+        }
+    }
+
     /**
      * Sends alarms that were blocked due to user applied background restrictions - either because
      * the user lifted those or the uid came to foreground.