diff --git a/libs/ardour/ardour/port_engine_shared.h b/libs/ardour/ardour/port_engine_shared.h
index c8313fa2b9..adef59cca6 100644
--- a/libs/ardour/ardour/port_engine_shared.h
+++ b/libs/ardour/ardour/port_engine_shared.h
@@ -27,7 +27,6 @@
 #include <string>
 #include <vector>
 
-
 #include "pbd/natsort.h"
 #include "pbd/rcu.h"
 
@@ -203,6 +202,8 @@ protected:
 		pthread_mutex_unlock (&_port_callback_mutex);
 	}
 
+	void process_connection_queue_locked (PortManager& mgr);
+
 	void port_connect_add_remove_callback () {
 		_port_change_flag.store (1);
 	}
diff --git a/libs/ardour/port_engine_shared.cc b/libs/ardour/port_engine_shared.cc
index 610c0e08b5..8eedac42c2 100644
--- a/libs/ardour/port_engine_shared.cc
+++ b/libs/ardour/port_engine_shared.cc
@@ -23,6 +23,7 @@
 #include "pbd/error.h"
 
 #include "ardour/port_engine_shared.h"
+#include "ardour/port_manager.h"
 
 #include "pbd/i18n.h"
 
@@ -828,6 +829,16 @@ PortEngineSharedImpl::update_system_port_latencies ()
 	}
 }
 
+void
+PortEngineSharedImpl::process_connection_queue_locked (PortManager& mgr)
+{
+	for (auto& c : _port_connection_queue) {
+		mgr.connect_callback (c->a, c->b, c->c);
+		delete c;
+	}
+	_port_connection_queue.clear ();
+}
+
 #ifndef NDEBUG
 void
 PortEngineSharedImpl::list_ports () const
diff --git a/libs/backends/alsa/alsa_audiobackend.cc b/libs/backends/alsa/alsa_audiobackend.cc
index 534bdca700..f3a09c1f04 100644
--- a/libs/backends/alsa/alsa_audiobackend.cc
+++ b/libs/backends/alsa/alsa_audiobackend.cc
@@ -2092,12 +2092,7 @@ AlsaAudioBackend::main_process_thread ()
 			if (!_port_connection_queue.empty ()) {
 				connections_changed = true;
 			}
-			while (!_port_connection_queue.empty ()) {
-				PortConnectData* c = _port_connection_queue.back ();
-				manager.connect_callback (c->a, c->b, c->c);
-				_port_connection_queue.pop_back ();
-				delete c;
-			}
+			process_connection_queue_locked (manager);
 			pthread_mutex_unlock (&_port_callback_mutex);
 		}
 		if (ports_changed) {
diff --git a/libs/backends/coreaudio/coreaudio_backend.cc b/libs/backends/coreaudio/coreaudio_backend.cc
index 5ceefae111..565e288d1c 100644
--- a/libs/backends/coreaudio/coreaudio_backend.cc
+++ b/libs/backends/coreaudio/coreaudio_backend.cc
@@ -1282,12 +1282,7 @@ CoreAudioBackend::pre_process ()
 		if (!_port_connection_queue.empty ()) {
 			connections_changed = true;
 		}
-		while (!_port_connection_queue.empty ()) {
-			PortConnectData *c = _port_connection_queue.back ();
-			manager.connect_callback (c->a, c->b, c->c);
-			_port_connection_queue.pop_back ();
-			delete c;
-		}
+		process_connection_queue_locked (manager);
 		pthread_mutex_unlock (&_port_callback_mutex);
 	}
 	if (ports_changed) {
diff --git a/libs/backends/dummy/dummy_audiobackend.cc b/libs/backends/dummy/dummy_audiobackend.cc
index 8f9d175eef..c30c7b84ec 100644
--- a/libs/backends/dummy/dummy_audiobackend.cc
+++ b/libs/backends/dummy/dummy_audiobackend.cc
@@ -1029,12 +1029,7 @@ DummyAudioBackend::main_process_thread ()
 			if (!_port_connection_queue.empty ()) {
 				connections_changed = true;
 			}
-			while (!_port_connection_queue.empty ()) {
-				PortConnectData *c = _port_connection_queue.back ();
-				manager.connect_callback (c->a, c->b, c->c);
-				_port_connection_queue.pop_back ();
-				delete c;
-			}
+			process_connection_queue_locked (manager);
 			pthread_mutex_unlock (&_port_callback_mutex);
 		}
 		if (ports_changed) {
diff --git a/libs/backends/portaudio/portaudio_backend.cc b/libs/backends/portaudio/portaudio_backend.cc
index e6a823dd60..2f011697a5 100644
--- a/libs/backends/portaudio/portaudio_backend.cc
+++ b/libs/backends/portaudio/portaudio_backend.cc
@@ -1827,12 +1827,7 @@ PortAudioBackend::process_port_connection_changes ()
 		if (!_port_connection_queue.empty ()) {
 			connections_changed = true;
 		}
-		while (!_port_connection_queue.empty ()) {
-			PortConnectData *c = _port_connection_queue.back ();
-			manager.connect_callback (c->a, c->b, c->c);
-			_port_connection_queue.pop_back ();
-			delete c;
-		}
+		process_connection_queue_locked (manager);
 		pthread_mutex_unlock (&_port_callback_mutex);
 	}
 	if (ports_changed) {
diff --git a/libs/backends/pulseaudio/pulseaudio_backend.cc b/libs/backends/pulseaudio/pulseaudio_backend.cc
index 2c2fac9adb..c7b732ffc2 100644
--- a/libs/backends/pulseaudio/pulseaudio_backend.cc
+++ b/libs/backends/pulseaudio/pulseaudio_backend.cc
@@ -1098,12 +1098,7 @@ PulseAudioBackend::main_process_thread ()
 			if (!_port_connection_queue.empty ()) {
 				connections_changed = true;
 			}
-			while (!_port_connection_queue.empty ()) {
-				PortConnectData* c = _port_connection_queue.back ();
-				manager.connect_callback (c->a, c->b, c->c);
-				_port_connection_queue.pop_back ();
-				delete c;
-			}
+			process_connection_queue_locked (manager);
 			pthread_mutex_unlock (&_port_callback_mutex);
 		}
 		if (ports_changed) {