[IVYDE-361] Deadlock in classpath container

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: master
• Component/s: classpath container
• Assignee: Nicolas Lalevée
• Reporter: Carsten Pfeiffer
• Created: 20/Mar/14 10:53
• Updated: 26/Apr/14 12:26
• Resolved: 26/Apr/14 12:26

Description

The change in IvyClasspathContainer (asyncExec -> syncExec) may unfortunately lead to deadlock situations. If the main thread attempts to execute a job while the resolve job is already running, the main thread waits for the resolve job to finish. The latter then attempts to syncExec() into the main thread, which won't work.

I'm wondering why the IvyClasspathContainer (now Impl) needs to syncExec() or asyncExec() at all. Do you remember why it cannot update the classpath in the background thread?

Thread [Worker-4] (Suspended)	
	waiting for: RunnableLock  (id=122)	
	Object.wait(long) line: not available [native method]	
	RunnableLock(Object).wait() line: 503	
	Synchronizer.syncExec(Runnable) line: 187	
	Display.syncExec(Runnable) line: 4330	
	IvyClasspathContainerImpl.setClasspathEntries(IClasspathEntry[]) line: 148	
	IvyClasspathContainerImpl.updateClasspathEntries(IClasspathEntry[]) line: 144	
	IvyClasspathResolver.postBatchResolve() line: 40	
	IvyResolveJob.doRun(IProgressMonitor) line: 263	
	IvyResolveJob.run(IProgressMonitor) line: 85	
	Worker.run() line: 54	

Thread [main] (Suspended)	
	owns: RunnableLock  (id=122)	
		waited by: Thread [Worker-4] (Suspended)	
	waiting for: Object  (id=123)	
	Object.wait(long) line: not available [native method]	
	Object.wait() line: 503	
	ThreadJob.waitForRun(ThreadJob, IProgressMonitor, InternalJob, Thread) line: 272	
	ThreadJob.joinRun(ThreadJob, IProgressMonitor) line: 199	
	ImplicitJobs.begin(ISchedulingRule, IProgressMonitor, boolean) line: 92	
	JobManager.beginRule(ISchedulingRule, IProgressMonitor) line: 286	
	WorkManager.checkIn(ISchedulingRule, IProgressMonitor) line: 118	
	Workspace.prepareOperation(ISchedulingRule, IProgressMonitor) line: 2282	
	Folder(Resource).refreshLocal(int, IProgressMonitor) line: 1655	
	ExternalFoldersManager.createLinkFolder(IPath, boolean, IProject, IProgressMonitor) line: 155	
	ExternalFoldersManager.createLinkFolder(IPath, boolean, IProgressMonitor) line: 145	
	ExternalFolderChange.updateExternalFoldersIfNecessary(boolean, IProgressMonitor) line: 48	
	SetContainerOperation(ChangeClasspathOperation).classpathChanged(ClasspathChange, boolean) line: 62	
	SetContainerOperation.executeOperation() line: 110	
	SetContainerOperation(JavaModelOperation).run(IProgressMonitor) line: 728	
	Workspace.run(IWorkspaceRunnable, ISchedulingRule, int, IProgressMonitor) line: 2344	
	SetContainerOperation(JavaModelOperation).runOperation(IProgressMonitor) line: 793	
	JavaCore.setClasspathContainer(IPath, IJavaProject[], IClasspathContainer[], IProgressMonitor) line: 4952	
	IvyClasspathContainerImpl.notifyUpdateClasspathEntries() line: 172	
	IvyClasspathContainerImpl$1.run() line: 162	
	RunnableLock.run() line: 35	
	Synchronizer.runAsyncMessages(boolean) line: 135	
	Display.runAsyncMessages(boolean) line: 3563	
	Display.readAndDispatch() line: 3212	
...

(This is basically a copy of my comments to the already close IVYDE-259.