always restore dlopen flag in dyndep (#22958)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/22958
When we use `extension_loader.DlopenGuard()` to dyndep or import modules, it sets a `RTLD_GLOBAL` flag, and restores the original flags after the `yield`. However, if the modules is not there, yield will fail, and the flags won't be restored, creating all kinds of symbol conflict problems.
Reviewed By: bddppq
Differential Revision: D16311949
fbshipit-source-id: 7b9ec6d60423ec5e78cae694b66c2f17493840b0
diff --git a/caffe2/python/extension_loader.py b/caffe2/python/extension_loader.py
index 10ac74b..c533ae6 100644
--- a/caffe2/python/extension_loader.py
+++ b/caffe2/python/extension_loader.py
@@ -18,6 +18,12 @@
if _set_global_flags:
old_flags = sys.getdlopenflags()
sys.setdlopenflags(old_flags | extra_flags)
- yield
- if _set_global_flags:
- sys.setdlopenflags(old_flags)
+
+ # in case we dlopen something that doesn't exist, yield will fail and throw;
+ # we need to remember reset the old flags to clean up, otherwise RTLD_GLOBAL
+ # flag will stick around and create symbol conflict problems
+ try:
+ yield
+ finally:
+ if _set_global_flags:
+ sys.setdlopenflags(old_flags)
