Android: Bluetooth failed to get port number

Question

I'm running into a problem using Bluetooth in my app. It seems that after 28 BluetoothSocket/BluetoothServerSockets have been created, all of the ports are taken. The sockets don't need to be opened simultaneously, it's just 28 sockets since Bluetooth was enabled.

This can be reproduced using the BluetoothChat sample provided in the Android Samples. Simply open and close the app 15 times (the app creates 2 sockets each time). On the 15th time, it will crash and will continue to crash until you disable and then re-enable Bluetooth:

12-06 18:43:58.177: E/BluetoothSocket(18530): bindListen, fail to get port number, exception: java.io.IOException: read failed, socket might closed, read ret: -1
12-06 18:43:58.193: E/BluetoothChatService(18530): Socket Type: Insecurelisten() failed
12-06 18:43:58.193: E/BluetoothChatService(18530): java.io.IOException: Error: -1
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.bluetooth.BluetoothAdapter.createNewRfcommSocketAndRecord(BluetoothAdapter.java:1035)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.bluetooth.BluetoothAdapter.listenUsingInsecureRfcommWithServiceRecord(BluetoothAdapter.java:982)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at com.example.android.BluetoothChat.BluetoothChatService$AcceptThread.<init>(BluetoothChatService.java:280)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at com.example.android.BluetoothChat.BluetoothChatService.start(BluetoothChatService.java:119)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at com.example.android.BluetoothChat.BluetoothChat.onResume(BluetoothChat.java:131)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1185)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.app.Activity.performResume(Activity.java:5182)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2732)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2771)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2235)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.os.Handler.dispatchMessage(Handler.java:99)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.os.Looper.loop(Looper.java:137)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at android.app.ActivityThread.main(ActivityThread.java:5039)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at java.lang.reflect.Method.invokeNative(Native Method)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at java.lang.reflect.Method.invoke(Method.java:511)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
12-06 18:43:58.193: E/BluetoothChatService(18530):  at dalvik.system.NativeStart.main(Native Method)

Is there any way to free the ports after the socket is closed?

Answer 1

I can verify this behavior on device that I have here; although the number of times required to crash in the same way varies by device (I think 20-25 times were required on the Galaxy Nexus running 4.2) so the available number of port handles seems to vary. I can also contribute the information that the issue is not a memory leak in the sample app (or your app for that matter) as all instances of BluetoothSocket have been released and closed by Dalvik. The steps listed here only tests the issue on BluetoothServerSocket, so its unclear if the problem is specifically related to that, though it seems unlikely.

At least on my devices, you cannot even start the app up again until toggling the Bluetooth adapter's status, so the problem is definitely in the underlying management of the connections on the stack.

I would file a bug with steps to reproduce here http://b.android.com and I'd be happy to upvote it.