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Posted to dev@sling.apache.org by "Carsten Ziegeler (JIRA)" <ji...@apache.org> on 2016/08/05 08:38:20 UTC
[jira] [Closed] (SLING-5847) Deadlock in
JcrResourceBundleProvider.getResourceBundleInternal when preloading is
enabled
[ https://issues.apache.org/jira/browse/SLING-5847?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Carsten Ziegeler closed SLING-5847.
-----------------------------------
> Deadlock in JcrResourceBundleProvider.getResourceBundleInternal when preloading is enabled
> ------------------------------------------------------------------------------------------
>
> Key: SLING-5847
> URL: https://issues.apache.org/jira/browse/SLING-5847
> Project: Sling
> Issue Type: Bug
> Components: Extensions
> Affects Versions: i18n 2.4.4
> Reporter: Konrad Windszus
> Assignee: Konrad Windszus
> Priority: Critical
> Fix For: i18n 2.4.8
>
>
> Under particular timing situations the {{reloadBundle}} job and a parallel call to {{JcrResourceBundleProvider.getResourceBundleInternal()}} might block each other and also all new threads calling {{JcrResourceBundleProvider.getResourceBundleInternal()}}.
> The thread dump in that situation looks like follows
> {code}
> "0:0:0:0:0:0:0:1 [1468492407436] GET <some request url> HTTP/1.1" - Thread t@69826
> java.lang.Thread.State: BLOCKED
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider.registerResourceBundle(JcrResourceBundleProvider.java:458)
> - waiting to lock <19c60354> (a org.apache.sling.i18n.impl.JcrResourceBundleProvider) owned by "pool-8-thread-5" t@111
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider.getResourceBundleInternal(JcrResourceBundleProvider.java:437)
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider.createResourceBundle(JcrResourceBundleProvider.java:480)
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider.getResourceBundleInternal(JcrResourceBundleProvider.java:435)
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider.getResourceBundle(JcrResourceBundleProvider.java:185)
> at org.apache.sling.i18n.impl.I18NFilter$CombinedBundleProvider.getResourceBundle(I18NFilter.java:217)
> at org.apache.sling.i18n.impl.I18NFilter$BaseI18NSlingHttpServletRequest.getResourceBundle(I18NFilter.java:311)
> at org.apache.sling.api.wrappers.SlingHttpServletRequestWrapper.getResourceBundle(SlingHttpServletRequestWrapper.java:115)
> at org.apache.sling.api.wrappers.SlingHttpServletRequestWrapper.getResourceBundle(SlingHttpServletRequestWrapper.java:115)
> at org.apache.sling.api.wrappers.SlingHttpServletRequestWrapper.getResourceBundle(SlingHttpServletRequestWrapper.java:115)
> at org.apache.sling.api.wrappers.SlingHttpServletRequestWrapper.getResourceBundle(SlingHttpServletRequestWrapper.java:115)
> at org.apache.sling.api.wrappers.SlingHttpServletRequestWrapper.getResourceBundle(SlingHttpServletRequestWrapper.java:115)
> at ...
> "pool-8-thread-5" - Thread t@111
> java.lang.Thread.State: WAITING
> at sun.misc.Unsafe.park(Native Method)
> - parking to wait for <69b06467> (a java.util.concurrent.Semaphore$NonfairSync)
> at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
> at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)
> at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:997)
> at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1304)
> at java.util.concurrent.Semaphore.acquire(Semaphore.java:312)
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider.getResourceBundleInternal(JcrResourceBundleProvider.java:429)
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider.createResourceBundle(JcrResourceBundleProvider.java:480)
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider.getResourceBundleInternal(JcrResourceBundleProvider.java:435)
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider.getResourceBundle(JcrResourceBundleProvider.java:185)
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider.reloadBundle(JcrResourceBundleProvider.java:357)
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider.reloadBundle(JcrResourceBundleProvider.java:352)
> at org.apache.sling.i18n.impl.JcrResourceBundleProvider$2.run(JcrResourceBundleProvider.java:320)
> - locked <19c60354> (a org.apache.sling.i18n.impl.JcrResourceBundleProvider)
> at org.apache.sling.commons.scheduler.impl.QuartzJobExecutor.execute(QuartzJobExecutor.java:115)
> at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
> at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:745)
> {code}
> Here is what happens internally:
> Thread 1 has acquired a semaphore for a specific key and now waits for the lock hold by thread 2 in
> {code}
> private void registerResourceBundle(Key key, JcrResourceBundle resourceBundle) {
> Dictionary<Object, Object> serviceProps = new Hashtable<Object, Object>();
> if (key.baseName != null) {
> serviceProps.put("baseName", key.baseName);
> }
> serviceProps.put("locale", key.locale.toString());
> ServiceRegistration serviceReg = bundleContext.registerService(ResourceBundle.class.getName(),
> resourceBundle, serviceProps);
> -> synchronized (this) {
> bundleServiceRegistrations.put(key, serviceReg);
> }
> {code}
> Thread 2 holds that lock in
> {code}
> private void scheduleReloadBundle(JcrResourceBundle bundle) {
> String baseName = bundle.getBaseName();
> Locale locale = bundle.getLocale();
> final Key key = new Key(baseName, locale);
> // defer this job
> ScheduleOptions options = scheduler.AT(new Date(System.currentTimeMillis() + invalidationDelay));
> final String jobName = "JcrResourceBundleProvider: reload bundle with key " + key.toString();
> scheduledJobNames.add(jobName);
> options.name(jobName);
> scheduler.schedule(new Runnable() {
> @Override
> public void run() {
> synchronized(JcrResourceBundleProvider.this) {
> -> reloadBundle(key);
> }
> scheduledJobNames.remove(jobName);
> }
> }, options);
> }
> {code}
> and now waits for the same semaphore that is being hold by thread 1 during the preloading.
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