diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 1da5147..69a1883 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -3951,7 +3951,10 @@
         mMixerStatus = MIXER_DRAIN_ALL;
         threadLoop_drain();
     }
-    mCallbackThread->exit();
+    if (mUseAsyncWrite) {
+        ALOG_ASSERT(mCallbackThread != 0);
+        mCallbackThread->exit();
+    }
     PlaybackThread::threadLoop_exit();
 }