Unhandled java.lang.NullPointerException: bio == null in io.grpc.okhttp.internal.framed.Http2$Reader.close

[ezrafernandez-toast]

What version of gRPC-Java are you using?

1.47.0

What is your environment?

Android 8, 9, 10, 12.

What did you expect to see?

When the underlying socket fails to close, possibly due to a race condition where it's already been closed, handle the thrown NPE.

What did you see instead?

An NPE is thrown and causes a crash.
https://issuetracker.google.com/issues/177450597
https://github.com/square/okhttp/pull/6533/files#diff-f88f9ac1ee194722f304572130663d2ba659e6e571fbc6dbfc6e639afe4003a4R502

Steps to reproduce the bug

Stack from a production report haven't been able to reproduce locally.

java.lang.NullPointerException: bio == null
    at org.conscrypt.NativeCrypto.SSL_pending_written_bytes_in_BIO(NativeCrypto.java)
    at org.conscrypt.NativeSsl$BioWrapper.getPendingWrittenBytes(NativeSsl.java:659)
    at org.conscrypt.ConscryptEngine.pendingOutboundEncryptedBytes(ConscryptEngine.java:565)
    at org.conscrypt.ConscryptEngineSocket.drainOutgoingQueue(ConscryptEngineSocket.java:568)
    at org.conscrypt.ConscryptEngineSocket.close(ConscryptEngineSocket.java:464)
    at org.conscrypt.ConscryptEngineSocket$SSLInputStream.close(ConscryptEngineSocket.java:732)
    at okio.InputStreamSource.close(JvmOkio.kt:111)
    at okio.AsyncTimeout$source$1.close(AsyncTimeout.kt:132)
    at okio.RealBufferedSource.close(RealBufferedSource.kt:480)
    at io.grpc.okhttp.internal.framed.Http2$Reader.close(Http2.java:370)
    at io.grpc.okhttp.OkHttpClientTransport$ClientFrameHandler.run(OkHttpClientTransport.java:1104)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
    at java.lang.Thread.run(Thread.java:764)

[sergiitk]

@temawi - preliminary investigation shows it's legit, please take a look at this code path:

grpc-java/okhttp/src/main/java/io/grpc/okhttp/OkHttpClientTransport.java

Lines 1129 to 1133 in 516f411

	try {
	frameReader.close();
	} catch (IOException ex) {
	log.log(Level.INFO, "Exception closing frame reader", ex);
	}

Would it make sense to do another catch block and check the description to be bio == null similar to what okhttp3 does in the PR diff linked by the OP?

[temawi]

Probably no harm in doing that, but there's just one thing I'm wondering about. The Conscrypt bug mentions that this problem can occur on Android 9 or 10, but this issue mentions it also happening on Android 12.

@ezrafernandez-toast Can you confirm that you really are seeing this on Android 12 devices as well?

[ezrafernandez-toast]

The majority of occurrences are on lower versions, with < 10% of reports on Android 12. I suppose it's possible the Conscrypt module has not updated on those devices?

[temawi]

I could buy that. We can get this change in to v1.61.0 that is releasing in the next few days, but there would not be patch release for v1.47.0 that you are using.

Is this actually causing you problems besides the occasional error message? The connection is already closed so hopefully you are not seeing any actual failed RPCs.

[ezrafernandez-toast]

I can nudge the team to update to 1.61. Our issue tracker reports these as fatal crashes.