218742 - Deadlock in LDAPConnection & LDAPConnThread

Status: RESOLVED DUPLICATE of bug 67413

(Directory Graveyard :: LDAP Java SDK, defect)

Description

[Peter Bower]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.3.1) Gecko/20030425
Build Identifier: Directory SDK 4.1 for Java Source Code


The LDAPConnection & LDAPConnThread threads can deadlock. The following
stack traces illustrate the problem.

"ExecuteThread: '4' for queue: 'default'" daemon prio=1 tid=0x826fbd8 
nid=0x407 waiting for monitor entry [0x7c6fe000..0x7c6ff870]
	at netscape.ldap.LDAPConnThread.getClientCount(LDAPConnThread.java:231)
	at netscape.ldap.LDAPConnection.disconnect(LDAPConnection.java:1896)
	at ...

"LDAPConnThread 192.168.224.224:389" daemon prio=1 tid=0x8566b48 nid=0x5f04 
waiting for monitor entry [0x873ff000..0x873ff870]
	at 
netscape.ldap.LDAPConnection.deregisterConnection(LDAPConnection.java:1937)
	at netscape.ldap.LDAPConnThread.cleanUp(LDAPConnThread.java:334)
	at netscape.ldap.LDAPConnThread.networkError(LDAPConnThread.java:627)
	at netscape.ldap.LDAPConnThread.run(LDAPConnThread.java:436)

The following code changes resolve the problem.

his  Patch contains Two Classes
  1.netscape.ldap.LDAPConnThread
  2.netscape.ldap.LDAPConection

The Diff for the modified source is as follows.
For nestcape.ldap.LDAPConnThread
	230c230
	<     /* synchronized */ int getClientCount() {
	---
	>     synchronized int getClientCount() {

For netscape.ldap.LDAPConnection
  259c259,261
< 
---
>     private boolean isCleaningUp;
>     private Object lock = new Object();
>     
1894d1896
<         
1900a1901
>         
1936,1940c1938,1959
<     synchronized void deregisterConnection() {
<         m_thread.deregister(this);
<         m_thread = null;
<         m_bound = false;
<     }
---
>      void deregisterConnection() {
>         if (isCleaningUp) 
>           return;
>         synchronized(lock) {
>           if (isCleaningUp) 
>             return;
>           else
>             isCleaningUp=true;
>         }
>         synchronized(this) {
>           m_thread.deregister(this);
>           m_thread = null;
>           m_bound = false;
>         }
>     }




Reproducible: Sometimes

Steps to Reproduce:
1. Have one thread attempt to bind to LDAP server - a failure occurs
2. After failure, thread calls conn.disconnect() to cleanup
3. LDAPConnection thread and user thread then deadlock

Actual Results:  
Both threads hang with deadlock.

Expected Results:  
See code changes.

Comment 1

[Mark Smith [:mcs]]

-> EY

Comment 2

[Erhyuan Tsai]

The jdb stack trace is same as one in bug 67413.
According to the Mirodrag's comments, this was fixed.
You seem using the old JDK 4.1, please try latest 4.17 from JDK page
at  http://www.mozilla.org/directory/javasdk.html.

*** This bug has been marked as a duplicate of 67413 ***