From 159d23be9f1aa9e389b2bca8aec1bb673e2e2549 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Thu, 15 Oct 2015 13:49:35 +0200
Subject: [PATCH] fix deadlock when removing subgroup bus w/sends.

...and potentially other route removals that involve
processor changes.
---
 libs/ardour/session.cc | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 479b433f29..1231212d2e 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -2064,6 +2064,10 @@ Session::resort_routes ()
 		return;
 	}
 
+	if (_route_deletion_in_progress) {
+		return;
+	}
+
 	{
 		RCUWriter<RouteList> writer (routes);
 		boost::shared_ptr<RouteList> r = writer.get_copy ();
@@ -3363,9 +3367,8 @@ Session::add_internal_send (boost::shared_ptr<Route> dest, boost::shared_ptr<Pro
 void
 Session::remove_routes (boost::shared_ptr<RouteList> routes_to_remove)
 {
-	PBD::Unwinder<bool> uw_flag (_route_deletion_in_progress, true);
-
 	{ // RCU Writer scope
+		PBD::Unwinder<bool> uw_flag (_route_deletion_in_progress, true);
 		RCUWriter<RouteList> writer (routes);
 		boost::shared_ptr<RouteList> rs = writer.get_copy ();