diff --git a/src/tracker_manager.cpp b/src/tracker_manager.cpp
index a240c57d6..dd2b7fb41 100644
--- a/src/tracker_manager.cpp
+++ b/src/tracker_manager.cpp
@@ -244,9 +244,10 @@ namespace libtorrent
 		}
 		else
 		{
+			// we need to post the error to avoid deadlock
 			if (boost::shared_ptr<request_callback> r = c.lock())
-				r->tracker_request_error(req, -1, "unknown protocol in tracker url: "
-					+ req.url);
+				ios.post(boost::bind(&request_callback::tracker_request_error, r, req, -1
+					, "unknown protocol in tracker url: " + req.url));
 			return;
 		}
 
diff --git a/test/setup_transfer.cpp b/test/setup_transfer.cpp
index f73eaec8b..85c59d146 100644
--- a/test/setup_transfer.cpp
+++ b/test/setup_transfer.cpp
@@ -217,6 +217,7 @@ boost::intrusive_ptr<torrent_info> create_torrent(std::ostream* file, int piece_
 	char const* tracker_url = "http://non-existent-name.com/announce";
 	// excercise the path when encountering invalid urls
 	char const* invalid_tracker_url = "http:";
+	char const* invalid_tracker_protocol = "foo://non/existent-name.com/announce";
 	
 	using namespace boost::filesystem;
 
@@ -226,6 +227,7 @@ boost::intrusive_ptr<torrent_info> create_torrent(std::ostream* file, int piece_
 	libtorrent::create_torrent t(fs, piece_size);
 	t.add_tracker(tracker_url);
 	t.add_tracker(invalid_tracker_url);
+	t.add_tracker(invalid_tracker_protocol);
 
 	std::vector<char> piece(piece_size);
 	for (int i = 0; i < int(piece.size()); ++i)