--- a/layout/base/nsLayoutUtils.cpp
+++ b/layout/base/nsLayoutUtils.cpp
@@ -3788,17 +3788,19 @@ nsLayoutUtils::PaintFrame(gfxContext* aR
     if (gfxEnv::DumpPaintToFile()) {
       fclose(gfxUtils::sDumpPaintFile);
     }
     gfxUtils::sDumpPaintFile = savedDumpFile;
 #endif
 
     std::stringstream lsStream;
     nsFrame::PrintDisplayList(&builder, list, lsStream);
-    layerManager->GetRoot()->SetDisplayListLog(lsStream.str().c_str());
+    if (layerManager->GetRoot()) {
+      layerManager->GetRoot()->SetDisplayListLog(lsStream.str().c_str());
+    }
   }
 
 #ifdef MOZ_DUMP_PAINTING
   if (gfxPrefs::DumpClientLayers()) {
     std::stringstream ss;
     FrameLayerBuilder::DumpRetainedLayerTree(layerManager, ss, false);
     print_stderr(ss);
   }