diff --git a/java/src/com/android/inputmethod/latin/UserHistoryDictionary.java b/java/src/com/android/inputmethod/latin/UserHistoryDictionary.java
index ca2d8840b..8c668b810 100644
--- a/java/src/com/android/inputmethod/latin/UserHistoryDictionary.java
+++ b/java/src/com/android/inputmethod/latin/UserHistoryDictionary.java
@@ -320,7 +320,11 @@ public final class UserHistoryDictionary extends ExpandableDictionary {
                     mUserHistoryDictionary.mBigramListLock.unlock();
                 }
             } else if (mUserHistoryDictionary.mBigramListLock.tryLock()) {
-                doWriteTaskLocked();
+                try {
+                    doWriteTaskLocked();
+                } finally {
+                    mUserHistoryDictionary.mBigramListLock.unlock();
+                }
             }
             return null;
         }