Cannot invoke "org.eclipse.jetty.io.RetainableByteBuffer.getByteBuffer()" because "buffer" is null

[lukaszn-rtbhouse]

Jetty version(s)

12.0.16

Jetty Environment

ee8

Java version/vendor (use: java -version)

openjdk version "22.0.2" 2024-07-16
OpenJDK Runtime Environment Temurin-22.0.2+9 (build 22.0.2+9)
OpenJDK 64-Bit Server VM Temurin-22.0.2+9 (build 22.0.2+9, mixed mode, sharing)

OS type/version

Linux 6.1.0-1015-oem #15-Ubuntu SMP PREEMPT_DYNAMIC Fri Jun 16 09:51:49 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

Description

We register a consistent rate of NPEs on multiple servers running jetty since at least Dec 2024. They surface when serializing JSON responses with Jackson. The response size is < 3kB.

Caused by: java.lang.NullPointerException: Cannot invoke "org.eclipse.jetty.io.RetainableByteBuffer.getByteBuffer()" because "buffer" is null
        at org.eclipse.jetty.io.ArrayByteBufferPool.release(ArrayByteBufferPool.java:281)
        at org.eclipse.jetty.io.ArrayByteBufferPool$Buffer.release(ArrayByteBufferPool.java:653)
        at org.eclipse.jetty.io.ArrayByteBufferPool.removeAndRelease(ArrayByteBufferPool.java:244)
        at org.eclipse.jetty.ee8.nested.HttpOutput.lockedReleaseBuffer(HttpOutput.java:599)
        at org.eclipse.jetty.ee8.nested.HttpOutput.onWriteComplete(HttpOutput.java:310)
        at org.eclipse.jetty.ee8.nested.HttpOutput.close(HttpOutput.java:573)
        at org.eclipse.jetty.io.WriteThroughWriter.close(WriteThroughWriter.java:103)
        at org.eclipse.jetty.ee8.nested.ResponseWriter.close(ResponseWriter.java:136)
        ...

Caused by: java.lang.NullPointerException: Cannot invoke "org.eclipse.jetty.io.RetainableByteBuffer.getByteBuffer()" because "buffer" is null
        at org.eclipse.jetty.io.ArrayByteBufferPool.release(ArrayByteBufferPool.java:281)
        at org.eclipse.jetty.io.ArrayByteBufferPool$Buffer.release(ArrayByteBufferPool.java:653)
        at org.eclipse.jetty.io.ArrayByteBufferPool.removeAndRelease(ArrayByteBufferPool.java:244)
        at org.eclipse.jetty.ee8.nested.HttpOutput.lockedReleaseBuffer(HttpOutput.java:599)
        at org.eclipse.jetty.ee8.nested.HttpOutput.onWriteComplete(HttpOutput.java:310)
        at org.eclipse.jetty.ee8.nested.HttpOutput.write(HttpOutput.java:781)
        at java.base/java.io.ByteArrayOutputStream.writeTo(ByteArrayOutputStream.java:170)
        at org.eclipse.jetty.io.WriteThroughWriter$Utf8Writer.append(WriteThroughWriter.java:335)
        at org.eclipse.jetty.io.WriteThroughWriter.write(WriteThroughWriter.java:133)
        at org.eclipse.jetty.ee8.nested.ResponseWriter.write(ResponseWriter.java:174)
        ...

How to reproduce?

Not sure yet. Flagging the issue in case somebody with context about Jetty can help pin down the problem.

[lorban]

This looks similar to #12623

[lorban]

It looks like ArrayByteBufferPool.removeAndRelease() is broken when the RetainableByteBuffer instance comes from QueuedPool, I could reproduce the problem here: #12799

We should be able to fix that shortly.