Index: lib/sanitizer_common/sanitizer_symbolizer.h
===================================================================
--- lib/sanitizer_common/sanitizer_symbolizer.h
+++ lib/sanitizer_common/sanitizer_symbolizer.h
@@ -177,6 +177,10 @@
   };
 };
 
+#ifdef SANITIZER_WINDOWS
+void InitializeDbgHelpIfNeeded();
+#endif
+
 }  // namespace __sanitizer
 
 #endif  // SANITIZER_SYMBOLIZER_H
Index: lib/sanitizer_common/sanitizer_symbolizer_win.cc
===================================================================
--- lib/sanitizer_common/sanitizer_symbolizer_win.cc
+++ lib/sanitizer_common/sanitizer_symbolizer_win.cc
@@ -42,6 +42,8 @@
   // FIXME: We don't call SymCleanup() on exit yet - should we?
 }
 
+}  // namespace
+
 // Initializes DbgHelp library, if it's not yet initialized. Calls to this
 // function should be synchronized with respect to other calls to DbgHelp API
 // (e.g. from WinSymbolizerTool).
@@ -97,8 +99,6 @@
   }
 }
 
-}  // namespace
-
 bool WinSymbolizerTool::SymbolizePC(uptr addr, SymbolizedStack *frame) {
   InitializeDbgHelpIfNeeded();
 
Index: lib/sanitizer_common/sanitizer_win.cc
===================================================================
--- lib/sanitizer_common/sanitizer_win.cc
+++ lib/sanitizer_common/sanitizer_win.cc
@@ -28,6 +28,7 @@
 #include "sanitizer_mutex.h"
 #include "sanitizer_placement_new.h"
 #include "sanitizer_stacktrace.h"
+#include "sanitizer_symbolizer.h"
 
 namespace __sanitizer {
 
@@ -733,6 +734,9 @@
   CONTEXT ctx = *(CONTEXT *)context;
   STACKFRAME64 stack_frame;
   memset(&stack_frame, 0, sizeof(stack_frame));
+
+  InitializeDbgHelpIfNeeded();
+
   size = 0;
 #if defined(_WIN64)
   int machine_type = IMAGE_FILE_MACHINE_AMD64;