diff --git a/mozilla/xpcom/ds/nsSupportsPrimitives.cpp b/mozilla/xpcom/ds/nsSupportsPrimitives.cpp
index cb5ed2e8bc9..5199e205997 100644
--- a/mozilla/xpcom/ds/nsSupportsPrimitives.cpp
+++ b/mozilla/xpcom/ds/nsSupportsPrimitives.cpp
@@ -809,7 +809,7 @@ NS_IMETHODIMP nsSupportsDoubleImpl::ToString(char **_retval)
 /***************************************************************************/
 
 
-NS_IMPL_ISUPPORTS1(nsSupportsVoidImpl, nsISupportsVoid)
+NS_IMPL_THREADSAFE_ISUPPORTS1(nsSupportsVoidImpl, nsISupportsVoid)
 
 nsSupportsVoidImpl::nsSupportsVoidImpl()
     : mData(nsnull)