diff --git a/telecomm/java/android/telecom/Log.java b/telecomm/java/android/telecom/Log.java
index 884dcf2..a34094c 100644
--- a/telecomm/java/android/telecom/Log.java
+++ b/telecomm/java/android/telecom/Log.java
@@ -69,6 +69,7 @@
     private static final Object sSingletonSync = new Object();
     private static EventManager sEventManager;
     private static SessionManager sSessionManager;
+    private static Object sLock = null;
 
     /**
      * Tracks whether user-activated extended logging is enabled.
@@ -388,6 +389,19 @@
     }
 
     /**
+     * Sets the main telecom sync lock used within Telecom.  This is used when building log messages
+     * so that we can identify places in the code where we are doing something outside of the
+     * Telecom lock.
+     * @param lock The lock.
+     */
+    public static void setLock(Object lock) {
+        // Don't do lock monitoring on user builds.
+        if (!Build.IS_USER) {
+            sLock = lock;
+        }
+    }
+
+    /**
      * If user enabled extended logging is enabled and the time limit has passed, disables the
      * extended logging.
      */
@@ -512,7 +526,10 @@
                     args.length);
             msg = format + " (An error occurred while formatting the message.)";
         }
-        return String.format(Locale.US, "%s: %s%s", prefix, msg, sessionPostfix);
+        // If a lock was set, check if this thread holds that lock and output an emoji that lets
+        // the developer know whether a log message came from within the Telecom lock or not.
+        String isLocked = sLock != null ? (Thread.holdsLock(sLock) ? "\uD83D\uDD12" : "❗") : "";
+        return String.format(Locale.US, "%s: %s%s%s", prefix, msg, sessionPostfix, isLocked);
     }
 
     /**