diff --git a/dom/src/threads/nsDOMThreadService.cpp b/dom/src/threads/nsDOMThreadService.cpp
index 47a5394e9b6..58f091211f4 100644
--- a/dom/src/threads/nsDOMThreadService.cpp
+++ b/dom/src/threads/nsDOMThreadService.cpp
@@ -320,7 +320,7 @@ public:
     // Make sure we have a JSContext to run everything on.
     JSContext* cx = (JSContext*)PR_GetThreadPrivate(gJSContextIndex);
     NS_ASSERTION(cx, "nsDOMThreadService didn't give us a context!");
-  
+
     JS_SetContextPrivate(cx, mWorker);
 
     // Tell the worker which context it will be using
@@ -347,6 +347,9 @@ public:
 protected:
 
   void RunQueue() {
+    JSContext* cx = (JSContext*)PR_GetThreadPrivate(gJSContextIndex);
+    NS_ASSERTION(cx, "nsDOMThreadService didn't give us a context!");
+
     while (1) {
       nsCOMPtr<nsIRunnable> runnable;
       {
@@ -367,6 +370,9 @@ protected:
         }
       }
 
+      // Clear out any old cruft hanging around in the regexp statics.
+      JS_ClearRegExpStatics(cx);
+
 #ifdef DEBUG
       nsresult rv =
 #endif
diff --git a/dom/src/threads/nsDOMWorkerSecurityManager.cpp b/dom/src/threads/nsDOMWorkerSecurityManager.cpp
index b94973abb4f..e14540cf428 100644
--- a/dom/src/threads/nsDOMWorkerSecurityManager.cpp
+++ b/dom/src/threads/nsDOMWorkerSecurityManager.cpp
@@ -89,14 +89,16 @@ NS_IMETHODIMP
 nsDOMWorkerSecurityManager::CanCreateInstance(JSContext* aJSContext,
                                               const nsCID& aCID)
 {
-  return NS_OK;
+  NS_NOTREACHED("Should not call this!");
+  return NS_ERROR_UNEXPECTED;
 }
 
 NS_IMETHODIMP
 nsDOMWorkerSecurityManager::CanGetService(JSContext* aJSContext,
                                           const nsCID& aCID)
 {
-  return NS_OK;
+  NS_NOTREACHED("Should not call this!");
+  return NS_ERROR_UNEXPECTED;
 }
 
 NS_IMETHODIMP
diff --git a/dom/src/threads/test/Makefile.in b/dom/src/threads/test/Makefile.in
index eca731da43e..c1db91fa44a 100644
--- a/dom/src/threads/test/Makefile.in
+++ b/dom/src/threads/test/Makefile.in
@@ -57,6 +57,8 @@ _TEST_FILES = \
   test_threadErrors.html \
   test_threadTimeouts.html \
   test_longThread.html \
+  test_recursion.html \
+  test_regExpStatics.html \
   test_xhr.html \
   testXHR.txt \
   $(NULL)