Index: libcfa/src/bits/containers.hfa
===================================================================
--- libcfa/src/bits/containers.hfa	(revision 2856982c6db55f1fdfb3012b77b490d999668ae8)
+++ libcfa/src/bits/containers.hfa	(revision be5f0a5b61b342b82e129e15c445f0be776c76d2)
@@ -152,4 +152,5 @@
 
 		void append( __queue(T) & this, T * val ) with(this) {
+			verify(get_next( *val ) == 0p);
 			verify(this.tail != 0p);
 			verify(*this.tail == 1p);
Index: libcfa/src/concurrency/invoke.h
===================================================================
--- libcfa/src/concurrency/invoke.h	(revision 2856982c6db55f1fdfb3012b77b490d999668ae8)
+++ libcfa/src/concurrency/invoke.h	(revision be5f0a5b61b342b82e129e15c445f0be776c76d2)
@@ -232,5 +232,5 @@
 
 		static inline thread$ *& get_next( thread$ & this ) __attribute__((const)) {
-			return this.link.next;
+			return this.user_link.next;
 		}
 
Index: libcfa/src/concurrency/monitor.cfa
===================================================================
--- libcfa/src/concurrency/monitor.cfa	(revision 2856982c6db55f1fdfb3012b77b490d999668ae8)
+++ libcfa/src/concurrency/monitor.cfa	(revision be5f0a5b61b342b82e129e15c445f0be776c76d2)
@@ -122,7 +122,7 @@
 
 		// Some one else has the monitor, wait in line for it
-		/* paranoid */ verify( thrd->link.next == 0p );
+		/* paranoid */ verify( thrd->user_link.next == 0p );
 		append( this->entry_queue, thrd );
-		/* paranoid */ verify( thrd->link.next == 1p );
+		/* paranoid */ verify( thrd->user_link.next == 1p );
 
 		unlock( this->lock );
@@ -233,7 +233,7 @@
 
 		// Some one else has the monitor, wait in line for it
-		/* paranoid */ verify( thrd->link.next == 0p );
+		/* paranoid */ verify( thrd->user_link.next == 0p );
 		append( this->entry_queue, thrd );
-		/* paranoid */ verify( thrd->link.next == 1p );
+		/* paranoid */ verify( thrd->user_link.next == 1p );
 		unlock( this->lock );
 
@@ -791,5 +791,5 @@
 	thread$ * new_owner = pop_head( this->entry_queue );
 	/* paranoid */ verifyf( !this->owner || active_thread() == this->owner, "Expected owner to be %p, got %p (r: %i, m: %p)", active_thread(), this->owner, this->recursion, this );
-	/* paranoid */ verify( !new_owner || new_owner->link.next == 0p );
+	/* paranoid */ verify( !new_owner || new_owner->user_link.next == 0p );
 	__set_owner( this, new_owner );
 
@@ -935,9 +935,17 @@
 	__queue_t(thread$) & entry_queue = monitors[0]->entry_queue;
 
+	#if defined( __CFA_WITH_VERIFY__ )
+		thread$ * last = 0p;
+	#endif
 	// For each thread in the entry-queue
 	for(	thread$ ** thrd_it = &entry_queue.head;
 		(*thrd_it) != 1p;
-		thrd_it = &(*thrd_it)->link.next
+		thrd_it = &get_next(**thrd_it)
 	) {
+		thread$ * curr = *thrd_it;
+
+		/* paranoid */ verifyf( !last || last->user_link.next == curr, "search not making progress, from %p (%p) to %p", last, last->user_link.next, curr );
+		/* paranoid */ verifyf( curr != last, "search not making progress, from %p to %p", last, curr );
+
 		// For each acceptable check if it matches
 		int i = 0;
@@ -946,5 +954,5 @@
 		for( __acceptable_t * it = begin; it != end; it++, i++ ) {
 			// Check if we have a match
-			if( *it == (*thrd_it)->monitors ) {
+			if( *it == curr->monitors ) {
 
 				// If we have a match return it
@@ -953,4 +961,8 @@
 			}
 		}
+
+		#if defined( __CFA_WITH_VERIFY__ )
+			last = curr;
+		#endif
 	}
 
@@ -1025,7 +1037,7 @@
 
 		// Some one else has the monitor, wait in line for it
-		/* paranoid */ verify( thrd->link.next == 0p );
+		/* paranoid */ verify( thrd->user_link.next == 0p );
 		append( this->entry_queue, thrd );
-		/* paranoid */ verify( thrd->link.next == 1p );
+		/* paranoid */ verify( thrd->user_link.next == 1p );
 
 		unlock( this->lock );