diff --git a/dom/ipc/TabChild.cpp b/dom/ipc/TabChild.cpp
index 954f205a3ab..06c9a96ff8b 100644
--- a/dom/ipc/TabChild.cpp
+++ b/dom/ipc/TabChild.cpp
@@ -1532,6 +1532,8 @@ TabChild::DestroyWindow()
             runnable->Dispatch();
         }
     }
+
+    mCachedFileDescriptorInfos.Clear();
 }
 
 void
diff --git a/dom/ipc/TabParent.cpp b/dom/ipc/TabParent.cpp
index d305a171779..a311f9a080f 100644
--- a/dom/ipc/TabParent.cpp
+++ b/dom/ipc/TabParent.cpp
@@ -149,7 +149,12 @@ private:
         FileDescriptor::PlatformHandleType handle =
             FileDescriptor::PlatformHandleType(PR_FileDesc2NativeHandle(mFD));
 
-        mozilla::unused << tabParent->SendCacheFileDescriptor(mPath, FileDescriptor(handle));
+        // Our TabParent may have been destroyed already.  If so, don't send any
+        // fds over, just go back to the IO thread and close them.
+        if (!tabParent->IsDestroyed()) {
+          mozilla::unused << tabParent->SendCacheFileDescriptor(mPath,
+                                                                FileDescriptor(handle));
+        }
 
         nsCOMPtr<nsIEventTarget> eventTarget;
         mEventTarget.swap(eventTarget);