Index: lib/asan/asan_win.cc
===================================================================
--- lib/asan/asan_win.cc
+++ lib/asan/asan_win.cc
@@ -291,6 +291,15 @@
   // On Win64, we map memory on demand with access violation handler.
   // Install our exception handler.
   CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler));
+
+  // This module must not be unloaded while ShadowExceptionHandler is still
+  // registered as an exception handler. Ideally we'd do proper cleanup with
+  // RemoveVectoredExceptionHandler, but in the short term just pin the DLL.
+  HMODULE unused;
+  CHECK(GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
+                           GET_MODULE_HANDLE_EX_FLAG_PIN,
+                           (LPCWSTR)&ShadowExceptionHandler,
+                           &unused));
 #endif
 }