guard dyndep with a lock (#26153)

Aapo Kyrola · facebook-github-bot · commit 20124c481420 · 2019-09-13T11:38:14.000-07:00
Summary: Pull Request resolved: #26153 I am suspecting that our multithreaded test-system causes issue with dyndep, if two places try to concurrently InitOpsLibrary. So perhaps we just guard this by a lock. This is just a guess-fix, as it is impossible to repro. Test Plan: sandcastle Reviewed By: bddppq Differential Revision: D17361310 fbshipit-source-id: 596634a2098b18881abbd26a5a727a5ba0d03b6e
diff --git a/caffe2/python/dyndep.py b/caffe2/python/dyndep.py
@@ -7,7 +7,7 @@
 
 import ctypes
 import os
-
+from threading import Lock
 from caffe2.python import core, extension_loader
 
 
@@ -36,15 +36,17 @@ def InitOpsLibrary(name):
 
 
 _IMPORTED_DYNDEPS = set()
+dll_lock = Lock()
 
 
 def GetImportedOpsLibraries():
     return _IMPORTED_DYNDEPS
 
 
 def _init_impl(path):
-    _IMPORTED_DYNDEPS.add(path)
-    with extension_loader.DlopenGuard():
-        ctypes.CDLL(path)
-    # reinitialize available ops
-    core.RefreshRegisteredOperators()
+    with dll_lock:
+        _IMPORTED_DYNDEPS.add(path)
+        with extension_loader.DlopenGuard():
+            ctypes.CDLL(path)
+        # reinitialize available ops
+        core.RefreshRegisteredOperators()
