diff --git a/modules/pacing/paced_sender.cc b/modules/pacing/paced_sender.cc
index 1d02fe9..cd298f9 100644
--- a/modules/pacing/paced_sender.cc
+++ b/modules/pacing/paced_sender.cc
@@ -196,11 +196,17 @@
 
 void PacedSender::SendRtpPacket(std::unique_ptr<RtpPacketToSend> packet,
                                 const PacedPacketInfo& cluster_info) {
+  critsect_.Leave();
   packet_router_->SendPacket(std::move(packet), cluster_info);
+  critsect_.Enter();
 }
 
 std::vector<std::unique_ptr<RtpPacketToSend>> PacedSender::GeneratePadding(
     DataSize size) {
-  return packet_router_->GeneratePadding(size.bytes());
+  std::vector<std::unique_ptr<RtpPacketToSend>> padding_packets;
+  critsect_.Leave();
+  padding_packets = packet_router_->GeneratePadding(size.bytes());
+  critsect_.Enter();
+  return padding_packets;
 }
 }  // namespace webrtc
diff --git a/test/direct_transport.cc b/test/direct_transport.cc
index f4ae047..818480b 100644
--- a/test/direct_transport.cc
+++ b/test/direct_transport.cc
@@ -55,6 +55,7 @@
 }
 
 void DirectTransport::SetReceiver(PacketReceiver* receiver) {
+  rtc::CritScope cs(&process_lock_);
   fake_network_->SetReceiver(receiver);
 }