diff --git a/libs/ui/FenceTime.cpp b/libs/ui/FenceTime.cpp
index 340231d..bdfe04b 100644
--- a/libs/ui/FenceTime.cpp
+++ b/libs/ui/FenceTime.cpp
@@ -279,8 +279,8 @@
 }
 
 void FenceTimeline::updateSignalTimes() {
+    std::lock_guard<std::mutex> lock(mMutex);
     while (!mQueue.empty()) {
-        std::lock_guard<std::mutex> lock(mMutex);
         std::shared_ptr<FenceTime> fence = mQueue.front().lock();
         if (!fence) {
             // The shared_ptr no longer exists and no one cares about the