Netty SslHandler引发IllegalReferenceCountException

Question

我正在使用Netty 4.0.36.Final编写客户端-服务器应用程序

测试工程师之一在客户端遇到此问题：

io.netty.handler.codec.DecoderException: io.netty.util.IllegalReferenceCountException: refCnt: 0, decrement: 1
    at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:418)
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:245)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:292)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:278)
    at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:266)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:292)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:278)
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:962)
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:131)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:528)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:485)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:399)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:371)
    at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:112)
    at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:137)
    at java.base/java.lang.Thread.run(Unknown Source)
Caused by: io.netty.util.IllegalReferenceCountException: refCnt: 0, decrement: 1
    at io.netty.buffer.AbstractReferenceCountedByteBuf.release(AbstractReferenceCountedByteBuf.java:101)
    at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1072)
    at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:904)
    at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:387)
    ... 15 common frames omitted

渠道管道：

@Override
public void initChannel(SocketChannel ch) throws Exception {
    ChannelPipeline pipeline = ch.pipeline();
    pipeline.addLast(sslContext.newHandler(ch.alloc()));
    pipeline.addLast(new AsnMessageDecoder());
    pipeline.addLast(new AsnMessageEncoder());
    pipeline.addLast(dataChannelHandler);
}

在某个时候，我向管道添加了另一个处理程序：

channel.pipeline().addFirst("idleStateHandler", new IdleStateHandler(180, 0, 0));

有两个ChannelInboundHandler的

public class AsnMessageDecoder extends ReplayingDecoder {
private static final Logger log = LoggerFactory.getLogger(AsnMessageDecoder.class);
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
    DERCoder coder = Asn.getDERCoder();
    coder.disableEncoderDebugging();
    coder.disableDecoderDebugging();
    coder.enableEncoderConstraints();
    coder.enableDecoderConstraints();
    coder.enableAutomaticEncoding();
    coder.enableAutomaticDecoding();
    coder.enableContainedValueEncoding();
    coder.enableContainedValueDecoding();
    try (ByteBufInputStream is = new ByteBufInputStream(in)) {
        out.add(coder.decode(is, new Message()));
    } catch (Exception e) {
        log.error("Failed to decode message", e);
    }
}

还有一个：

abstract class BaseChannelHandler<T extends ChannelContext> extends SimpleChannelInboundHandler<Message> {
private final Logger log = LoggerFactory.getLogger(getClass());

private final T channelContext;
private final ClientConfiguration clientConfiguration;
private final Writer writer;
private final ClientService service;

BaseChannelHandler(T channelContext,
                   ClientConfiguration clientConfiguration,
                   Writer writer,
                   ClientService service) {
    this.channelContext = channelContext;
    this.clientConfiguration = clientConfiguration;
    this.writer = writer;
    this.service = service;
}

@Override
public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
    log.debug("{} channelRegistered", getClass().getSimpleName());
}

@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
    log.debug("{} channelActive", getClass().getSimpleName());
    channelContext.connectState();
}

@Override
protected void channelRead0(ChannelHandlerContext ctx, Message msg) throws Exception {
    log.debug("{} channelRead0 msg = {}", getClass().getSimpleName(), msg);
    channelContext.handleMessage(msg);
    if (clientConfiguration.isWritingOutputEnabled()) {
        writer.writeXml(msg);
    }
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
    log.error(getClass().getSimpleName() + " exceptionCaught", cause);
    ctx.close();
    service.stop();
}

@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
    log.debug("{} channelInactive", getClass().getSimpleName());
}

@Override
public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
    log.debug("{} channelUnregistered", getClass().getSimpleName());
}

@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
    if (evt instanceof IdleStateEvent) {
        ctx.disconnect();
    }
}

我无法重现问题。 在我的本地计算机上，它工作正常。 看着wirweshark并没有给我任何提示。 看起来像正常断开连接。 我不太确定下一步该如何定位该问题。 您能给我一些解决该问题的建议吗？

Answer 1

因此，这似乎是netty版本中的一个错误（该版本很旧）。 升级到4.1.24.Final修复了它。