[jboss-jira] [JBoss JIRA] Closed: (JBRULES-2114) Drools hangs with deadlock after it has initialized a rule (in multithreaded environment)

Drools hangs with deadlock after it has initialized a rule (in multithreaded environment) ----------------------------------------------------------------------------------------- Key: JBRULES-2114 URL: https://jira.jboss.org/browse/JBRULES-2114 Project: Drools Issue Type: Bug Security Level: Public(Everyone can see) Components: drools-core Affects Versions: 4.0.6 Reporter: Andrey Nechaev Assignee: Edson Tirelli Priority: Critical Fix For: 5.1.0.FINAL Attachments: patch-AbstractRuleBase Here is a scenario when drools core hangs with a deadlock: Suppose we heve a rule throwing an exception in the RHS. So, if: 1. Thread A updates the Rule Base with the rule 2. The rule fires (current thread is Thread A) 3. Rule's RHS throws an exception (still having Thread A as current) 4. Thread B tries to update the Rule Base or the Working Memory (for example, the Thread B inserts a fact) in such a case the Thread B falls into infinite wait() loop. Here is the test case showing such a behavior: package com.test; import java.io.StringReader; import org.drools.RuleBase; import org.drools.RuleBaseFactory; import org.drools.WorkingMemory; import org.drools.compiler.PackageBuilder; public class DroolsTest2 { private final static String rule = "" + "package test\n" + "import com.test.DroolsTest2;\n" + "rule test\n" + "\twhen\n" + "\tthen\n" + "\t\tDroolsTest2.fail();" + "end"; private static Object sem = new Object(); private static boolean seed = false; public static void main(String[] args) throws Exception { final RuleBase rb = RuleBaseFactory.newRuleBase(); final WorkingMemory wm = rb.newStatefulSession(); new Thread(new Runnable() { @Override public void run() { seed = false; PackageBuilder bld = new PackageBuilder(); try { bld.addPackageFromDrl(new StringReader(rule)); rb.addPackage(bld.getPackage()); } catch(Exception e) { } finally { synchronized (sem) { seed = true; sem.notify(); } } } }).start(); Thread ins = new Thread(new Runnable() { @Override public void run() { while(!seed) { synchronized (sem) { try { sem.wait(); } catch (InterruptedException e) {} } } wm.insert(new Object()); } }); ins.start(); ins.join(); } public static void fail() { throw new IllegalStateException("fail!"); } }