diff --git a/src/asio/io_service.cpp b/src/asio/io_service.cpp
index fa01540a..441bfc67 100644
--- a/src/asio/io_service.cpp
+++ b/src/asio/io_service.cpp
@@ -42,6 +42,7 @@ io_service::~io_service() BOOST_NOEXCEPT
 #if 0
     BOOST_FOREACH( detail::fiber_base::ptr_t const& p, wqueue_)
     { p.first->release(); }
+    wqueue_.clear();
 #endif
 }
 
@@ -78,12 +79,10 @@ io_service::spawn( detail::fiber_base::ptr_t const& f)
 void
 io_service::evaluate_( detail::fiber_base::ptr_t const& f) {
     if ( f->is_waiting() )
-    {
         wqueue_.push_back(
             std::make_pair(
                 f,
                 boost::asio::io_service::work( io_service_) ) );
-    }
     else if ( f->is_ready() ) spawn( f);
     else BOOST_ASSERT_MSG( false, "fiber with invalid state in ready-queue");
 }
diff --git a/src/round_robin.cpp b/src/round_robin.cpp
index d06a1929..4443fe3e 100644
--- a/src/round_robin.cpp
+++ b/src/round_robin.cpp
@@ -108,7 +108,7 @@ round_robin::run()
         rqueue_.pop_front();
 
         if ( f->is_ready() ) break;
-        if ( f->is_waiting() ) wqueue_.push_back( f);
+        else if ( f->is_waiting() ) wqueue_.push_back( f);
         else BOOST_ASSERT_MSG( false, "fiber with invalid state in ready-queue");
     }
     while ( true);