diff --git a/src/fuse_open.cpp b/src/fuse_open.cpp
index 0004a2d1..0319628f 100644
--- a/src/fuse_open.cpp
+++ b/src/fuse_open.cpp
@@ -348,7 +348,7 @@ namespace FUSE
     pt.visit(fusepath_,
              [](const PTMap::value_type &x_)
              {
-               std::lock(mutex);
+               std::lock(x_.mutex);
              });
 
     return open2(fusepath_,ffi_);