diff --git a/builder.py b/builder.py
index 15f435c..4cc0fc8 100644
--- a/builder.py
+++ b/builder.py
@@ -353,18 +353,18 @@ def main(targets, shouldbuildfunc):
                 backoff *= 2
                 if vars.DEBUG_LOCKS:
                     warn('%s (WAITING)\n' % _nice(t))
+                try:
+                    lock.check()
+                except state.CyclicDependencyError:
+                    err('cyclic dependency while building %s\n' % _nice(t))
+                    retcode[0] = 208
+                    return retcode[0]
                 # this sequence looks a little silly, but the idea is to
                 # give up our personal token while we wait for the lock to
                 # be released; but we should never run get_token() while
                 # holding a lock, or we could cause deadlocks.
                 jwack.release_mine()
-                try:
-                    lock.waitlock()
-                except state.CyclicDependencyError:
-                    err('cyclic dependency while building %s\n' % _nice(t))
-                    jwack.get_token(t)
-                    retcode[0] = 208
-                    return retcode[0]
+                lock.waitlock()
                 lock.unlock()
                 jwack.get_token(t)
                 lock.trylock()
diff --git a/jwack.py b/jwack.py
index 1242e60..80786b4 100644
--- a/jwack.py
+++ b/jwack.py
@@ -18,8 +18,8 @@ def _debug(s):
 
 def _release(n):
     global _mytokens
-    _debug('release(%d)\n' % n)
     _mytokens += n
+    _debug('release(%d) -> %d\n' % (n, _mytokens))
     if _mytokens > 1:
         os.write(_fds[1], 't' * (_mytokens-1))
         _mytokens = 1
@@ -28,8 +28,9 @@ def _release(n):
 def release_mine():
     global _mytokens
     assert(_mytokens >= 1)
-    os.write(_fds[1], 't')
     _mytokens -= 1
+    _debug('release_mine() -> %d\n' % _mytokens)
+    os.write(_fds[1], 't')
 
 
 def _timeout(sig, frame):
@@ -198,7 +199,7 @@ def wait_all():
             bb += b
             if not b: break
         if len(bb) != _toplevel-1:
-            raise Exception('on exit: expected %d tokens; found only %r' 
+            raise Exception('on exit: expected %d tokens; found %r'
                             % (_toplevel-1, len(bb)))
         os.write(_fds[1], bb)
 
diff --git a/state.py b/state.py
index c857ebf..d27f472 100644
--- a/state.py
+++ b/state.py
@@ -348,8 +348,14 @@ class Lock:
         if self.lockfile is not None:
             os.close(self.lockfile)
 
-    def trylock(self):
+    def check(self):
         assert(not self.owned)
+        if str(self.fid) in vars.get_locks():
+            # Lock already held by parent: cyclic dependence
+            raise CyclicDependencyError()
+
+    def trylock(self):
+        self.check()
         try:
             fcntl.lockf(self.lockfile, fcntl.LOCK_EX|fcntl.LOCK_NB, 0, 0)
         except IOError, e:
@@ -361,10 +367,7 @@ class Lock:
             self.owned = True
 
     def waitlock(self):
-        assert(not self.owned)
-        if str(self.fid) in vars.get_locks():
-            # Lock already held by parent: cyclic dependence
-            raise CyclicDependencyError()
+        self.check()
         fcntl.lockf(self.lockfile, fcntl.LOCK_EX, 0, 0)
         self.owned = True