diff --git a/gfx/layers/ipc/CompositorBridgeParent.cpp b/gfx/layers/ipc/CompositorBridgeParent.cpp
index db6a52bb038f..f4769df26f86 100644
--- a/gfx/layers/ipc/CompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/CompositorBridgeParent.cpp
@@ -241,7 +241,6 @@ void CompositorBridgeParent::FinishShutdown() {
   }
 
   // TODO: this should be empty by now...
-  MonitorAutoLock lock(sIndirectLayerTreesLock);
   sIndirectLayerTrees.clear();
 }