diff --git a/services/core/java/com/android/server/AlarmManagerService.java b/services/core/java/com/android/server/AlarmManagerService.java
index 312553a980b2a..4dd88b20fb7f1 100644
--- a/services/core/java/com/android/server/AlarmManagerService.java
+++ b/services/core/java/com/android/server/AlarmManagerService.java
@@ -2547,7 +2547,9 @@ class AlarmManagerService extends SystemService {
                 } else {
                     // Just in case -- even though no wakeup flag was set, make sure
                     // we have updated the kernel to the next alarm time.
-                    rescheduleKernelAlarmsLocked();
+                    synchronized (mLock) {
+                        rescheduleKernelAlarmsLocked();
+                    }
                 }
             }
         }