merged fix from RC_0_16

ChangeLog

@@ -25,6 +25,7 @@
 	* fix uTP edge case where udp socket buffer fills up
 	* fix nagle implementation in uTP
 
+	* fix deadlock caused by some UDP tracker failures
 	* fix potential integer overflow issue in timers on windows
 	* minor fix to peer_proportional mixed_mode algorithm (TCP limit could go too low)
 	* graceful pause fix

include/libtorrent/tracker_manager.hpp

@@ -188,6 +188,8 @@ namespace libtorrent
 		virtual void on_timeout(error_code const& ec) = 0;
 		virtual ~timeout_handler() {}
 
+		io_service& get_io_service() { return m_timeout.get_io_service(); }
+
 #if !defined TORRENT_VERBOSE_LOGGING \
 	&& !defined TORRENT_LOGGING \
 	&& !defined TORRENT_ERROR_LOGGING
@@ -229,7 +231,6 @@ namespace libtorrent
 
 		tracker_request const& tracker_req() const { return m_req; }
 
-		void fail_disp(error_code ec) { fail(ec); }
 		void fail(error_code const& ec, int code = -1, char const* msg = ""
 			, int interval = 0, int min_interval = 0);
 		virtual void start() = 0;
@@ -242,6 +243,9 @@ namespace libtorrent
 		virtual bool on_receive_hostname(error_code const& ec, char const* hostname
 			, char const* buf, int size) { return false; }
 
+		boost::intrusive_ptr<tracker_connection> self()
+		{ return boost::intrusive_ptr<tracker_connection>(this); }
+
 #if !defined TORRENT_VERBOSE_LOGGING \
 	&& !defined TORRENT_LOGGING \
 	&& !defined TORRENT_ERROR_LOGGING
@@ -249,6 +253,9 @@ namespace libtorrent
 	protected:
 #endif
 
+		void fail_impl(error_code const& ec, int code = -1, std::string msg = std::string()
+			, int interval = 0, int min_interval = 0);
+
 		boost::weak_ptr<request_callback> m_requester;
 
 		tracker_manager& m_man;

src/http_tracker_connection.cpp

@@ -107,8 +107,7 @@ namespace libtorrent
 			std::size_t pos = url.find("announce");
 			if (pos == std::string::npos)
 			{
-				m_ios.post(boost::bind(&http_tracker_connection::fail_disp, self()
-					, error_code(errors::scrape_not_available)));
+				tracker_connection::fail(error_code(errors::scrape_not_available));
 				return;
 			}
 			url.replace(pos, 8, "scrape");

src/tracker_manager.cpp

@@ -163,9 +163,17 @@ namespace libtorrent
 
 	void tracker_connection::fail(error_code const& ec, int code
 		, char const* msg, int interval, int min_interval)
+	{
+		// we need to post the error to avoid deadlock
+			get_io_service().post(boost::bind(&tracker_connection::fail_impl
+					, self(), ec, code, std::string(msg), interval, min_interval));
+	}
+
+	void tracker_connection::fail_impl(error_code const& ec, int code
+		, std::string msg, int interval, int min_interval)
 	{
 		boost::shared_ptr<request_callback> cb = requester();
-		if (cb) cb->tracker_request_error(m_req, code, ec, msg
+		if (cb) cb->tracker_request_error(m_req, code, ec, msg.c_str()
 			, interval == 0 ? min_interval : interval);
 		close();
 	}

src/udp_tracker_connection.cpp

@@ -95,9 +95,7 @@ namespace libtorrent
 
 		if (ec)
 		{
-			// never call fail() when the session mutex is locked!
-			m_ses.m_io_service.post(boost::bind(
-				&tracker_connection::fail_disp, self(), ec));
+			tracker_connection::fail(ec);
 			return;
 		}