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Bug 246893

Summary:	deadlock during Go To Symbol
Product:	platform	Reporter:	Vladimir Voskresensky <vv159170>
Component:	Filesystems	Assignee:	Jaroslav Havlin <jhavlin>
Status:	RESOLVED FIXED
Severity:	normal	CC:	gteichrow
Priority:	P2
Version:	8.1
Hardware:	All
OS:	All
Issue Type:	DEFECT	Exception Reporter:
Attachments:	threads dump Proposed Patch

Description Vladimir Voskresensky 2014-09-05 10:38:08 UTC

I pressed Ctrl+Shift+O and IDE became frozen.
I see blocked Watcher.register in EDT

Comment 1 Vladimir Voskresensky 2014-09-05 10:39:03 UTC

Created attachment 149048 [details]
threads dump

  Product Version         = NetBeans IDE Dev (Build 20140905-ecb25fa5bd60) (#ecb25fa5bd60)
  Operating System        = SunOS version 5.11 running on amd64
  Java; VM; Vendor        = 1.7.0_67; Java HotSpot(TM) 64-Bit Server VM 24.65-b04; Oracle Corporation
  Runtime                 = Java(TM) SE Runtime Environment 1.7.0_67-b01
  Java Home               = /usr/jdk/instances/jdk1.7.0_67/jre

Comment 2 Ondrej Vrabec 2014-09-05 11:09:44 UTC

there is no deadlock, but VCSFileProxy should definitely not trying to add listeners in EDT

Comment 3 Jaroslav Havlin 2014-09-05 11:53:37 UTC

Unfortunately, I think there is a deadlock involving Watcher and FileChangedManager.

Thread "Refresh-After-WindowActivated" wants to perform some low-priority I/O operation using "FileChangedManager.idleIO". In this operation, it needs to register a listener, so it takes Watcher's lock, but it is then blocked in FileChangedManager because it is waiting for some (just started) hi-priority operation to complete.

Thread "org.netbeans.modules.jumpto.symbol.ContentProviderImpl" performs the high-priority operation (FileChangedManager.priorityIO), but it cannot complete it as it has to wait forever to get the Watcher's lock (meanwhile retrieved by "Refresh-After-WindowActivated").

This deadlock can occur only with NIO2 Notifier (currently used probably only on Solaris OS) which invokes Java SecurityManager when registering a watch. (FileChangedManager is set as SecurityManager in NetBeans.)

Comment 4 Ondrej Vrabec 2014-09-05 12:16:48 UTC

ok, then. Fix the deadlock and then reassign back to me, because the I/O in EDT should be avoided as well.

Comment 5 Jaroslav Havlin 2014-09-08 12:47:33 UTC

Created attachment 149065 [details]
Proposed Patch

Patch that fixes the problem. Reviews are welcome.
I'll integrate it at the end of this week, unless there are any objections.

Comment 6 Jaroslav Havlin 2014-09-11 13:04:38 UTC

Fixed - http://hg.netbeans.org/core-main/rev/8908192d8d66

If you want to integrate the fix in the patch (801patch1-candidate), please verify if carefully (especially on Solaris). If the change breaks something, the impact can be quite large.
Thank you.

Comment 7 Jaroslav Havlin 2014-09-11 13:11:55 UTC

(In reply to Ondrej Vrabec from comment #4)
> ok, then. Fix the deadlock and then reassign back to me, because the I/O in
> EDT should be avoided as well.
Reported as separate bug 247030.

Comment 8 Quality Engineering 2014-09-13 04:52:39 UTC

Integrated into 'main-silver', will be available in build *201409130001* on http://bits.netbeans.org/dev/nightly/ (upload may still be in progress)

Changeset: http://hg.netbeans.org/main-silver/rev/8908192d8d66
User: Jaroslav Havlin <jhavlin@netbeans.org>
Log: #246893: Deadlock during Go To Symbol

FileChangedManager's "lock" has to be always taken before Watcher's lock.

Comment 9 Jaroslav Havlin 2015-08-12 08:29:48 UTC

*** Bug 252393 has been marked as a duplicate of this bug. ***