diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 8b4b9352641..dea71ce031e 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -6148,6 +6148,7 @@ nsDocShell::GetRootScrollableView(nsIScrollableView ** aOutScrollView)
 
     nsCOMPtr<nsIPresShell> shell;
     NS_ENSURE_SUCCESS(GetPresShell(getter_AddRefs(shell)), NS_ERROR_FAILURE);
+    NS_ENSURE_TRUE(shell, NS_ERROR_NULL_POINTER);
 
     nsCOMPtr<nsIViewManager> viewManager;
     NS_ENSURE_SUCCESS(shell->GetViewManager(getter_AddRefs(viewManager)),