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https://issues.apache.org/jira/browse/KARAF-5315?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Martin Krüger closed KARAF-5315.
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> Race condition during shutdown using SIGTERM
> --------------------------------------------
>
> Key: KARAF-5315
> URL: https://issues.apache.org/jira/browse/KARAF-5315
> Project: Karaf
> Issue Type: Bug
> Affects Versions: 4.0.9
> Environment: Linux using systemd
> Reporter: Martin Krüger
> Assignee: Jean-Baptiste Onofré
> Priority: Major
> Fix For: 4.0.10, 4.1.3, 4.2.0.M1
>
> Attachments:
> 0001-KARAF-5315-Synchronize-access-to-SimpleFileLock.patch,
> 0002-KARAF-5315-Signal-handler-stops-framework-directly.patch
>
>
> During shutdown using SIGTERM there is a race condition.
> {noformat}
> Error occurred shutting down framework:
> java.nio.channels.ClosedChannelException
> java.nio.channels.ClosedChannelException
> at sun.nio.ch.FileLockImpl.release(FileLockImpl.java:58)
> at
> org.apache.karaf.main.lock.SimpleFileLock.release(SimpleFileLock.java:78)
> at org.apache.karaf.main.Main.destroy(Main.java:642)
> at org.apache.karaf.main.Main.main(Main.java:188)
> Main process exited, code=exited, status=254
> {noformat}
> There are several problems in the code of the Main class.
> # The variable indicating the exit condition ( private boolean exiting; line
> 89) used in several threads is not volatile.
> # The same is true for the lock (private Lock lock; line 87).
> # The signal handler calls Main.this.destroy(); which is called by the main
> thread again after leaving function awaitShutdown() (line 581)
> Because the destroy() function releases the lock in the finally block the
> lock is released twice. The used implementation is the SimpleFileLock. In
> there the release() function is not synchronized. Since the channel of the
> file-lock is closed the second call will result in the exception.
> To get rid of the double release the SimpleFileLock.release() function should
> be synchronized. But I am not sure if the double call of the Main.destroy()
> function is an even bigger problem because all activators are stopped twice
> too.
> {code}
> while (timeout > 0) {
> timeout -= step;
> FrameworkEvent event = framework.waitForStop(step);
> if (event.getType() != FrameworkEvent.WAIT_TIMEDOUT) {
> activatorManager.stopKarafActivators();
> return true;
> }
> }
> {code}
> Maybe synchronizing the Main.destroy() function is a good idea too or find a
> different way to have the signal handler stopping the framework by just
> signaling the stop and waking up the main thread ....
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