native-image compilation of epoll transport fails

Expected behavior

My small repro compiles as a native image and works as expected if I use Nio* family of transports. My expectation was that switching to epoll transport would similarly work.

Actual behavior

If I switch to epoll (linux-x86_64) I get a compilation error:

Error: Classes that should be initialized at run time got initialized during image building:
 io.netty.util.AbstractReferenceCounted the class was requested to be initialized at build time (from the command line). io.netty.util.AbstractReferenceCounted has been initialized without the native-image initialization instrumentation and the stack trace can't be tracked. Try avoiding to initialize the class that caused initialization of io.netty.util.AbstractReferenceCounted

com.oracle.svm.core.util.UserError$UserException: Classes that should be initialized at run time got initialized during image building:
 io.netty.util.AbstractReferenceCounted the class was requested to be initialized at build time (from the command line). io.netty.util.AbstractReferenceCounted has been initialized without the native-image initialization instrumentation and the stack trace can't be tracked. Try avoiding to initialize the class that caused initialization of io.netty.util.AbstractReferenceCounted

	at com.oracle.svm.core.util.UserError.abort(UserError.java:65)
	at com.oracle.svm.hosted.classinitialization.ConfigurableClassInitialization.checkDelayedInitialization(ConfigurableClassInitialization.java:510)
	at com.oracle.svm.hosted.classinitialization.ClassInitializationFeature.duringAnalysis(ClassInitializationFeature.java:187)
	at com.oracle.svm.hosted.NativeImageGenerator.lambda$runPointsToAnalysis$8(NativeImageGenerator.java:710)
	at com.oracle.svm.hosted.FeatureHandler.forEachFeature(FeatureHandler.java:63)
	at com.oracle.svm.hosted.NativeImageGenerator.runPointsToAnalysis(NativeImageGenerator.java:710)
	at com.oracle.svm.hosted.NativeImageGenerator.doRun(NativeImageGenerator.java:530)
	at com.oracle.svm.hosted.NativeImageGenerator.lambda$run$0(NativeImageGenerator.java:445)
	at java.base/java.util.concurrent.ForkJoinTask$AdaptedRunnableAction.exec(ForkJoinTask.java:1407)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:177)

Minimal yet complete reproducer code (or URL to code)

Here’s a repro: https://github.com/perezd/netty-epoll-native-repro

w/ Bazel 3.5.0 installed, run this command from the root of the project:

bazel run :main-native

Netty version

4.1.52.Final (linux-x86_64)

JVM version (e.g. java -version)

java -version openjdk version “11.0.8” 2020-07-14 OpenJDK Runtime Environment (build 11.0.8+10-post-Ubuntu-0ubuntu120.04) OpenJDK 64-Bit Server VM (build 11.0.8+10-post-Ubuntu-0ubuntu120.04, mixed mode, sharing)

OS version (e.g. uname -a)

Linux desktop 5.4.0-48-generic #52-Ubuntu SMP Thu Sep 10 10:58:49 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

I’ve searched around and attempted various workarounds but nothing seems to work.

[jamesward]

I also ran into this again with Netty 4.1.70 and GraalVM 21.3.0 but was able to get it working with:

  --initialize-at-run-time=io.netty.channel.DefaultFileRegion
  --initialize-at-run-time=io.netty.channel.epoll.Native
  --initialize-at-run-time=io.netty.channel.epoll.Epoll
  --initialize-at-run-time=io.netty.channel.epoll.EpollEventLoop
  --initialize-at-run-time=io.netty.channel.epoll.EpollEventArray
  --initialize-at-run-time=io.netty.channel.kqueue.KQueue
  --initialize-at-run-time=io.netty.channel.kqueue.KQueueEventLoop
  --initialize-at-run-time=io.netty.channel.kqueue.KQueueEventArray
  --initialize-at-run-time=io.netty.channel.kqueue.Native
  --initialize-at-run-time=io.netty.channel.unix.Limits
  --initialize-at-run-time=io.netty.channel.unix.Errors
  --initialize-at-run-time=io.netty.channel.unix.IovArray

[jacekgajek]

Hello, I try to build a native image of a Micronaut service and have lots of similar errors

(Error: Classes that should be initialized at run time got initialized during image building: io.grpc.netty.shaded.io.netty.buffer.ByteBufUtil the class was requested to be initialized at run time (from jar:file:///home/jacek/.gradle/caches/modules-2/files-2.1/io.grpc/grpc-netty-shaded/1.41.0/43fee785c101b3bfa3f7d916d8b47d5d736cbff2/grpc-netty-shaded-1.41.0.jar!/META-INF/native-image/io.grpc.netty.shaded.io.netty/buffer/native-image.properties with ‘io.grpc.netty.shaded.io.netty.buffer.ByteBufUtil’). To see why io.grpc.netty.shaded.io.netty.buffer.ByteBufUtil got initialized use --trace-class-initialization=io.grpc.netty.shaded.io.netty.buffer.ByteBufUtil io.grpc.netty.shaded.io.netty.buffer.ByteBufAllocator the class was requested to be initialized at run time (from jar:file:///home/jacek/.gradle/caches/modules-2/files-2.1/io.grpc/grpc-netty-shaded/1.41.0/43fee785c101b3bfa3f7d916d8b47d5d736cbff2/grpc-netty-shaded-1.41.0.jar!/META-INF/native-image/io.grpc.netty.shaded.io.netty/buffer/native-image.properties with ‘io.grpc.netty.shaded.io.netty.buffer.ByteBufAllocator’). To see why io.grpc.netty.shaded.io.netty.buffer.ByteBufAllocator got initialized use --trace-class-initialization=io.grpc.netty.shaded.io.netty.buffer.ByteBufAllocator …

Is there a known solution or a workaround for this? From various suggestions I tried

  buildArgs.add(
        "--initialize-at-run-time=" +
         "io.grpc.netty.shaded.io.netty.util.internal.logging.Log4JLogger," +
            "io.grpc.netty.shaded.io.netty.handler.ssl.JdkNpnApplicationProtocolNegotiator," +
            "io.netty.handler.ssl.util.ThreadLocalInsecureRandom," +
            "io.netty.channel.unix,io.netty.channel.epoll,io.netty.channel.kqueue"
)

but it didn’t help. Is there some radical workaround which maybe sacrifice performance but at least allow to successfully compile?