diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
index 9a84e5a..f80dd85 100644
--- a/src/mesa/main/fbobject.c
+++ b/src/mesa/main/fbobject.c
@@ -93,6 +93,8 @@ delete_dummy_framebuffer(struct gl_framebuffer *fb)
 void
 _mesa_init_fbobjects(GLcontext *ctx)
 {
+   _glthread_INIT_MUTEX(DummyFramebuffer.Mutex);
+   _glthread_INIT_MUTEX(DummyRenderbuffer.Mutex);
    DummyFramebuffer.Delete = delete_dummy_framebuffer;
    DummyRenderbuffer.Delete = delete_dummy_renderbuffer;
 }