使用Byteman COMPILE选项触发VerifyError，求排查规则问题

在Felix Server中运行应用时，需要监控RestMonitoringJobRegistry.updateMonitoredState方法的执行时间，编写了两个带COMPILE选项的Byteman规则：入口记录开始时间，出口计算耗时。规则提交无报错，但运行时触发VerifyError，移除COMPILE选项后规则运行正常。

应用代码 #

package com.mypackage.monitoring.client;

public class RestMonitoringJobRegistry extends BaseMonitoringJobRegistry
{           
    public synchronized <T> void updateMonitoredState(
            MonitoringJob<T> aInMonitoringJob, T aInState)
    {
        if (aInMonitoringJob == null || aInState == null)
        {
            TPAResources.debug(logger,
                    "Cannot send: missing required information.");
            return;
        }

        // 省略其他逻辑
    }
}

入口规则 #

RULE record_startTime_RestMonitoringJobRegistry
CLASS com.mypackage.monitoring.client.RestMonitoringJobRegistry
METHOD updateMonitoredState
COMPILE
AT ENTRY
BIND
    LOGGER:Logger = com.mypackage.monitoring.client.RestMonitoringJobRegistry.logger;
    startTime = System.currentTimeMillis()
IF true
DO
    LOGGER.info("[JA] AT ENTRY");
    link(Thread.currentThread(), "startTime", startTime);
ENDRULE

出口规则 #

RULE check_duration_RestMonitoringJobRegistry
CLASS com.mypackage.monitoring.client.RestMonitoringJobRegistry
METHOD updateMonitoredState
COMPILE
AT EXIT
BIND
    LOGGER:Logger = com.mypackage.monitoring.client.RestMonitoringJobRegistry.logger;
    startTime:int = unlink(Thread.currentThread(), "startTime");
    endTime = System.currentTimeMillis()
IF true
DO
    LOGGER.info("[JA] AT EXIT: updateMonitoredState took elapsedTime [" + (endTime - startTime) + "] $aInMonitoringJob.getKey() [" + $aInMonitoringJob.getKey() +"]");
ENDRULE

错误日志 #

{"host":"host","level":"ERROR","log":{"classname":"com.pkg.as.service.log.impl.asrlog.Stdout2Log4jOutputStream$StdoutRedirectorThread:104","message":"check_duration_RestMonitoringJobRegistry : java.lang.VerifyError: (class: org/jboss/byteman/rule/helper/Helper_HelperAdapter_Compiled_53, method: execute0 signature: ()V) Expecting to find integer on stack","stacktrace":"","threadname":"StdoutThread"},"process":"run","service":"","time":"2024-03-22T00:20:50.725Z","timezone":"Asia/Kolkata","type":"log"}

移除COMPILE后的正常日志 #

{"host":"host","level":"INFO","log":{"classname":"org.jboss.byteman.rule.helper.Helper_HelperAdapter_Compiled_51:11","message":"[JA] AT ENTRY","stacktrace":"","threadname":"MonitoringJobRegistry-4"},"process":"execute0","service":"","time":"2024-03-22T00:20:30.714Z","timezone":"Asia/Kolkata","type":"log"}

问题出在类型不匹配：

• 入口规则中System.currentTimeMillis()返回long类型，通过link绑定到线程的startTime是long值。
• 出口规则错误地将startTime声明为int类型，unlink取出的long值被强制转换为int，在COMPILE模式下，Byteman生成的字节码严格遵循类型校验，栈上实际是long类型却被当作int处理，触发VerifyError。
• 移除COMPILE选项后，Byteman使用解释模式执行规则，对类型校验相对宽松，隐式处理了类型转换，因此无报错。

修正后的规则 #

将startTime的类型统一为long，同时建议入口规则也显式声明类型保持一致：

修正后的入口规则 #

RULE record_startTime_RestMonitoringJobRegistry
CLASS com.mypackage.monitoring.client.RestMonitoringJobRegistry
METHOD updateMonitoredState
COMPILE
AT ENTRY
BIND
    LOGGER:Logger = com.mypackage.monitoring.client.RestMonitoringJobRegistry.logger;
    startTime:long = System.currentTimeMillis()
IF true
DO
    LOGGER.info("[JA] AT ENTRY");
    link(Thread.currentThread(), "startTime", startTime);
ENDRULE

修正后的出口规则 #

RULE check_duration_RestMonitoringJobRegistry
CLASS com.mypackage.monitoring.client.RestMonitoringJobRegistry
METHOD updateMonitoredState
COMPILE
AT EXIT
BIND
    LOGGER:Logger = com.mypackage.monitoring.client.RestMonitoringJobRegistry.logger;
    startTime:long = unlink(Thread.currentThread(), "startTime");
    endTime:long = System.currentTimeMillis()
IF true
DO
    LOGGER.info("[JA] AT EXIT: updateMonitoredState took elapsedTime [" + (endTime - startTime) + "] $aInMonitoringJob.getKey() [" + $aInMonitoringJob.getKey() +"]");
ENDRULE

内容的提问来源于stack exchange，提问作者Asif Ansari