Agents launched under openjdk9 appear to be incompatible with masters running openjdk 7 or 8.

At the end of a Execute Shell step, an exception is thrown in what appears to be the process cleanup code. In the example below, the Execute Shell indicated a failure, but the issue occurs even if Execute Shell succeeds.

<... normal test execution...>
Build step 'Execute shell' marked build as failure
FATAL: Remote call on <redacted remote name> failed
java.io.IOException: Remote call on <redacted remote name> failed
at hudson.remoting.Channel.call(Channel.java:789)
at hudson.Launcher$RemoteLauncher.kill(Launcher.java:953)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:540)
at hudson.model.Run.execute(Run.java:1738)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:410)
Caused by: java.lang.LinkageError
at hudson.util.ProcessTree$UnixReflection.<clinit>(ProcessTree.java:634)
at hudson.util.ProcessTree$UnixProcess.kill(ProcessTree.java:571)
at hudson.util.ProcessTree$UnixProcess.killRecursively(ProcessTree.java:592)
at hudson.util.ProcessTree$Unix.killAll(ProcessTree.java:513)
at hudson.Launcher$RemoteLauncher$KillTask.call(Launcher.java:965)
at hudson.Launcher$RemoteLauncher$KillTask.call(Launcher.java:956)
at hudson.remoting.UserRequest.perform(UserRequest.java:120)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:332)
at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1158)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:632)
at java.lang.Thread.run(Thread.java:804)
at ......remote call to <redacted remote name>(Native Method)
at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1416)
at hudson.remoting.UserResponse.retrieve(UserRequest.java:220)
at hudson.remoting.Channel.call(Channel.java:781)
... 6 more
Caused by: java.lang.ClassNotFoundException: Classloading from system classloader disabled
at hudson.remoting.RemoteClassLoader$ClassLoaderProxy.fetch4(RemoteClassLoader.java:770)
at hudson.remoting.RemoteClassLoader$ClassLoaderProxy.fetch3(RemoteClassLoader.java:803)
at sun.reflect.GeneratedMethodAccessor10261.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at hudson.remoting.RemoteInvocationHandler$RPCRequest.perform(RemoteInvocationHandler.java:608)
at hudson.remoting.Request$2.run(Request.java:332)
at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)
at org.jenkinsci.remoting.CallableDecorator.call(CallableDecorator.java:18)
at hudson.remoting.CallableDecoratorList$1.call(CallableDecoratorList.java:21)
at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
at ......remote call to channel(Native Method)
at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1416)
at hudson.remoting.Request.call(Request.java:172)
at hudson.remoting.RemoteInvocationHandler.invoke(RemoteInvocationHandler.java:253)
at com.sun.proxy.$Proxy6.fetch3(Unknown Source)
at hudson.remoting.RemoteClassLoader.findClass(RemoteClassLoader.java:171)
at java.lang.ClassLoader.loadClass(ClassLoader.java:486)
at java.lang.ClassLoader.loadClass(ClassLoader.java:419)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:294)
at hudson.util.ProcessTree$UnixReflection.<clinit>(ProcessTree.java:623)
at hudson.util.ProcessTree$UnixProcess.kill(ProcessTree.java:571)
at hudson.util.ProcessTree$UnixProcess.killRecursively(ProcessTree.java:592)
at hudson.util.ProcessTree$Unix.killAll(ProcessTree.java:513)
at hudson.Launcher$RemoteLauncher$KillTask.call(Launcher.java:965)
at hudson.Launcher$RemoteLauncher$KillTask.call(Launcher.java:956)
at hudson.remoting.UserRequest.perform(UserRequest.java:120)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:332)
at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1158)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:632)
at java.lang.Thread.run(Thread.java:804)
Sending e-mails to: redacted@redacted
Finished: FAILURE