diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index 4610ae3..f36ee92 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -2710,6 +2710,7 @@
   
   bool Logging = ::getenv("LIBCLANG_LOGGING");
   ASTUnit *CXXUnit = static_cast<ASTUnit *>(tu->TUData);
+  ASTUnit::ConcurrencyCheck Check(*CXXUnit);
   const FileEntry *File = static_cast<const FileEntry *>(file);
   SourceLocation SLoc = CXXUnit->getLocation(File, line, column);
   if (SLoc.isInvalid()) {