diff --git a/media/mtp/AsyncIO.cpp b/media/mtp/AsyncIO.cpp
index e77ad38..bfb07dc 100644
--- a/media/mtp/AsyncIO.cpp
+++ b/media/mtp/AsyncIO.cpp
@@ -96,6 +96,10 @@
 
 } // end anonymous namespace
 
+aiocb::~aiocb() {
+    CHECK(!thread.joinable());
+}
+
 void aio_pool_init(void(f)(int)) {
     CHECK(done == 1);
     done = 0;