diff --git a/libguile/threads.c b/libguile/threads.c
index 15e4919..417c225 100644
--- a/libguile/threads.c
+++ b/libguile/threads.c
@@ -1603,19 +1603,20 @@ fat_mutex_unlock (SCM mutex, SCM cond,
   if (! (SCM_UNBNDP (cond)))
     {
       c = SCM_CONDVAR_DATA (cond);
+
+      if (m->level > 0)
+        m->level--;
+      if (m->level == 0)
+        {
+          /* Change the owner of MUTEX.  */
+          t->mutexes = scm_delq_x (mutex, t->mutexes);
+          m->owner = unblock_from_queue (m->waiting);
+        }
+
       while (1)
 	{
 	  int brk = 0;
 
-	  if (m->level > 0)
-	    m->level--;
-	  if (m->level == 0)
-	    {
-	      /* Change the owner of MUTEX.  */
-	      t->mutexes = scm_delq_x (mutex, t->mutexes);
-	      m->owner = unblock_from_queue (m->waiting);
-	    }
-
 	  t->block_asyncs++;
 
 	  err = block_self (c->waiting, cond, &m->lock, waittime);