--- a/netwerk/protocol/http/nsHttpConnectionMgr.cpp
+++ b/netwerk/protocol/http/nsHttpConnectionMgr.cpp
@@ -403,16 +403,21 @@ private:
 nsresult
 nsHttpConnectionMgr::SpeculativeConnect(nsHttpConnectionInfo *ci,
                                         nsIInterfaceRequestor *callbacks,
                                         uint32_t caps,
                                         NullHttpTransaction *nullTransaction)
 {
     MOZ_ASSERT(NS_IsMainThread(), "nsHttpConnectionMgr::SpeculativeConnect called off main thread!");
 
+    if (!IsNeckoChild()) {
+        // HACK: make sure PSM gets initialized on the main thread.
+        net_EnsurePSMInit();
+    }
+
     LOG(("nsHttpConnectionMgr::SpeculativeConnect [ci=%s]\n",
          ci->HashKey().get()));
 
     nsCOMPtr<nsISpeculativeConnectionOverrider> overrider =
         do_GetInterface(callbacks);
 
     bool allow1918 = overrider ? overrider->GetAllow1918() : false;