diff --git a/content/base/src/nsDocument.cpp b/content/base/src/nsDocument.cpp
index 92c928dfa79c..138ca8a574fd 100644
--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -5344,8 +5344,9 @@ nsDocument::GetAnimationController()
   // one and only SVG documents and the like will call this
   if (mAnimationController)
     return mAnimationController;
-  // Refuse to create an Animation Controller if SMIL is disabled
-  if (!NS_SMILEnabled())
+  // Refuse to create an Animation Controller if SMIL is disabled, and also
+  // for data documents.
+  if (!NS_SMILEnabled() || mLoadedAsData)
     return nsnull;
 
   mAnimationController = NS_NewSMILAnimationController(this);
diff --git a/content/smil/crashtests/529387-1-helper.svg b/content/smil/crashtests/529387-1-helper.svg
new file mode 100644
index 000000000000..7885ab71fd4a
--- /dev/null
+++ b/content/smil/crashtests/529387-1-helper.svg
@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg">
+  <text y="20pt">abc
+    <animate attributeName="opacity" from="1" to="0" begin="0s" dur="2s"/>
+  </text>
+</svg>
diff --git a/content/smil/crashtests/529387-1.xhtml b/content/smil/crashtests/529387-1.xhtml
new file mode 100644
index 000000000000..de3dbec34cff
--- /dev/null
+++ b/content/smil/crashtests/529387-1.xhtml
@@ -0,0 +1,7 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <script>
+    var p = new XMLHttpRequest();
+    p.open("GET", "529387-1-helper.svg", false);
+    p.send();
+  </script>
+</html>
diff --git a/content/smil/crashtests/crashtests.list b/content/smil/crashtests/crashtests.list
index 4ca09fa7ac0d..2533a13b5aa1 100644
--- a/content/smil/crashtests/crashtests.list
+++ b/content/smil/crashtests/crashtests.list
@@ -2,3 +2,4 @@ load 523188-1.svg
 load 525099-1.svg
 load 526875-1.svg
 load 526875-2.svg
+load 529387-1.xhtml
