I'm using a custom loginmodule and a custom Principal. As the loginmodule accesses a bean, I stacked the RunAsLoginModule on top of the custom one.
Sometimes, I'm getting the following exception when accessing a bean remotely. I'm not able to find a deterministic way to reproduce it.

java.lang.IllegalArgumentException: Either callerSubject or callerRunAs should be non-null
org.jboss.security.plugins.javaee.EJBAuthorizationHelper.authorize(EJBAuthorizationHelper.java:78)
org.jboss.ejb3.security.RoleBasedAuthorizationInterceptorv2.invoke(RoleBasedAuthorizationInterceptorv2.java:189)
org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
org.jboss.ejb3.security.Ejb3AuthenticationInterceptorv2.invoke(Ejb3AuthenticationInterceptorv2.java:186)
org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:41)
org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
org.jboss.ejb3.BlockContainerShutdownInterceptor.invoke(BlockContainerShutdownInterceptor.java:67)
org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
org.jboss.aspects.currentinvocation.CurrentInvocationInterceptor.invoke(CurrentInvocationInterceptor.java:67)
org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
org.jboss.ejb3.stateless.StatelessContainer.dynamicInvoke(StatelessContainer.java:421)
org.jboss.ejb3.session.InvokableContextClassProxyHack._dynamicInvoke(InvokableContextClassProxyHack.java:53)
org.jboss.aop.Dispatcher.invoke(Dispatcher.java:91)
org.jboss.aspects.remoting.AOPRemotingInvocationHandler.invoke(AOPRemotingInvocationHandler.java:82)
org.jboss.remoting.ServerInvoker.invoke(ServerInvoker.java:897)
org.jboss.remoting.transport.socket.ServerThread.completeInvocation(ServerThread.java:768)
org.jboss.remoting.transport.socket.ServerThread.processInvocation(ServerThread.java:721)
org.jboss.remoting.transport.socket.ServerThread.dorun(ServerThread.java:548)
org.jboss.remoting.transport.socket.ServerThread.run(ServerThread.java:234)
org.jboss.remoting.MicroRemoteClientInvoker.invoke(MicroRemoteClientInvoker.java:213)
org.jboss.remoting.Client.invoke(Client.java:1917)
org.jboss.remoting.Client.invoke(Client.java:768)
org.jboss.aspects.remoting.InvokeRemoteInterceptor.invoke(InvokeRemoteInterceptor.java:60)
org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
org.jboss.aspects.remoting.ClusterChooserInterceptor.invoke(ClusterChooserInterceptor.java:84)
org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
org.jboss.aspects.tx.ClientTxPropagationInterceptor.invoke(ClientTxPropagationInterceptor.java:61)
org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
org.jboss.ejb3.security.client.SecurityClientInterceptor.invoke(SecurityClientInterceptor.java:65)
org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
org.jboss.ejb3.remoting.ClusteredIsLocalInterceptor.invoke(ClusteredIsLocalInterceptor.java:54)
org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
org.jboss.aspects.remoting.PojiProxy.invoke(PojiProxy.java:62)
$Proxy5.invoke(Unknown Source)
org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:188)
$Proxy32.getBatch(Unknown Source)