diff --git a/softkeymaster/include/keymaster/softkeymaster.h b/softkeymaster/include/keymaster/softkeymaster.h
index 17d1389..e4b173c 100644
--- a/softkeymaster/include/keymaster/softkeymaster.h
+++ b/softkeymaster/include/keymaster/softkeymaster.h
@@ -40,5 +40,6 @@
 
 int openssl_open(const hw_module_t* module, const char* name, hw_device_t** device);
 
-struct keystore_module softkeymaster_module;
+extern struct keystore_module softkeymaster_module;
+
 #endif  // SOFTKEYMASTER_INCLUDE_KEYMASTER_SOFTKEYMASTER_H_