[jcifs] Threads locked while calling SmbFile.getSecurity

[Marc Brette]

I have an issue where 16 threads calling SmbFile.getSecurity are blocked.
When I have only 15 threads, it works fine (note that each thread accesses a
different document, but on the same server).
I use JCIFS 1.2.21. And tested on different shared drives (with and without
credentials). I initially tested with 1.2.18 with a more complex example so
I guess it s not specific to the JCIFS version.
Is it something known ? I saw some thread talking about deadlock in jcifs
but it seemed to be in situation unlikely to occur in reality.

Here is my code:
import java.util.List;
import java.util.Arrays;

import jcifs.smb.SmbFile;
import jcifs.smb.NtlmPasswordAuthentication;

public class TestDeadlock
{
   static
   {
      System.setProperty("java.protocol.handler.pkgs", "jcifs");
   }

   public static void main(String[] args) throws InterruptedException
   {
      final List<String> dataset = Arrays.asList(
          "smb://frgr1dev1/Y_Drive/Documentation/javadocs/ant/ant 1.6.2
api/org/apache/tools/zip/package-frame.html"
          , "smb://frgr1dev1/Y_Drive/Documentation/javadocs/ant/ant 1.6.2
api/org/apache/tools/ant/taskdefs/optional/ejb/BorlandDeploymentTool.html"
          , "smb://frgr1dev1/Y_Drive/Documentation/javadocs/ant/ant 1.6.2
api/org/apache/tools/ant/types/Reference.html"
          ,
"smb://frgr1dev1/Y_Drive/Documentation/javadocs/jdk/jdk1.3.1/javax/rmi/package-use.html"
          ,
"smb://frgr1dev1/Y_Drive/Documentation/javadocs/jdk/jdk1.3.1/java/io/FilterOutputStream.html"
          ,
"smb://frgr1dev1/Y_Drive/Documentation/javadocs/jdk/jdk1.3.1/javax/accessibility/AccessibleTableModelChange.html"
          ,
"smb://frgr1dev1/Y_Drive/Documentation/javadocs/jdk/jdk1.4.2/org/omg/stub/java/"
          ,
"smb://frgr1dev1/Y_Drive/Documentation/javadocs/jdk/jdk1.3.1/javax/transaction/InvalidTransactionException.html"
          , "smb://frgr1dev1/Y_Drive/Documentation/javadocs/ant/ant 1.6.2
api/org/apache/tools/ant/taskdefs/optional/junit/DOMUtil.NodeListImpl.html"
          ,
"smb://frgr1dev1/Y_Drive/Documentation/javadocs/jdk/jdk1.4.2/java/awt/geom/AffineTransform.html"
          ,
"smb://frgr1dev1/Y_Drive/Documentation/javadocs/jdk/jdk1.3.1/javax/naming/ldap/package-frame.html"
          ,
"smb://frgr1dev1/Y_Drive/Documentation/javadocs/jdk/jdk1.3.1/java/awt/Shape.html"
          ,
"smb://frgr1dev1/Y_Drive/Documentation/javadocs/jdk/jdk1.4.2/javax/transaction/xa/package-summary.html"
          , "smb://frgr1dev1/Y_Drive/Documentation/javadocs/ant/ant 1.6.2
api/org/apache/tools/ant/taskdefs/optional/script/package-summary.html"
          ,
"smb://frgr1dev1/Y_Drive/Documentation/javadocs/jdk/jdk1.4.2/javax/net/ServerSocketFactory.html");

      int start = 0;
      int end = 15;
      Thread[] workers = new Thread[end - start];
      for (int i = start; i < end; i++)
      {
         final String url = dataset.get(i);
         workers[i - start] = new Thread(new Runnable()
         {
            public void run()
            {
               try
               {
                  SmbFile f = new SmbFile(url);
                  System.out.println(url + " security = " +
f.getSecurity(true)); //This trace never shows up

               } catch (Throwable e)
               {
                  e.printStackTrace();
               }
            }
         });
      }

      for (Thread worker : workers)
      {
         worker.start();
      }

      for (Thread worker : workers)
      {
         worker.join();
      }
   }
}

Here is an extract of the threads stacktrace dump:

"Thread-4" prio=6 tid=0x0033dde8 nid=0x64d4 in Object.wait()
[0x031bf000..0x031bf9e8]
    at java.lang.Object.wait(Native Method)
    - waiting on <0x2465e260> (a [Ljava.lang.Object;)
    at java.lang.Object.wait(Object.java:474)
    at jcifs.smb.BufferCache.getBuffers(BufferCache.java:55)
    - locked <0x2465e260> (a [Ljava.lang.Object;)
    at jcifs.smb.SmbTransport.send(SmbTransport.java:547)
    at jcifs.smb.SmbSession.send(SmbSession.java:239)
    - locked <0x2467f780> (a java.lang.Object)
    at jcifs.smb.SmbTree.send(SmbTree.java:109)
    at jcifs.smb.SmbFile.send(SmbFile.java:695)
    at
jcifs.smb.TransactNamedPipeOutputStream.write(TransactNamedPipeOutputStream.java:65)
    at
jcifs.dcerpc.DcerpcPipeHandle.doSendFragment(DcerpcPipeHandle.java:59)
    at jcifs.dcerpc.DcerpcHandle.sendrecv(DcerpcHandle.java:164)
    at jcifs.dcerpc.msrpc.LsaPolicyHandle.<init>(LsaPolicyHandle.java:34)
    at jcifs.smb.SID.resolveSids0(SID.java:136)
    at jcifs.smb.SID.resolveSids(SID.java:179)
    at jcifs.smb.SmbFile.processAces(SmbFile.java:2774)
    at jcifs.smb.SmbFile.getSecurity(SmbFile.java:2808)
    at TestDeadlock$1.run(TestDeadlock.java:84)
    at java.lang.Thread.run(Thread.java:595)

"Thread-3" prio=6 tid=0x0033dc60 nid=0x4494 waiting for monitor entry
[0x0317f000..0x0317fce8]
    at jcifs.smb.SmbTree.treeConnect(SmbTree.java:128)
    - waiting to lock <0x2467f780> (a java.lang.Object)
    at jcifs.smb.SmbTree.send(SmbTree.java:64)
    at jcifs.smb.SmbFile.send(SmbFile.java:695)
    at
jcifs.smb.TransactNamedPipeOutputStream.write(TransactNamedPipeOutputStream.java:65)
    at
jcifs.dcerpc.DcerpcPipeHandle.doSendFragment(DcerpcPipeHandle.java:59)
    at jcifs.dcerpc.DcerpcHandle.sendrecv(DcerpcHandle.java:164)
    at jcifs.dcerpc.msrpc.LsaPolicyHandle.<init>(LsaPolicyHandle.java:34)
    at jcifs.smb.SID.resolveSids0(SID.java:136)
    at jcifs.smb.SID.resolveSids(SID.java:179)
    at jcifs.smb.SmbFile.processAces(SmbFile.java:2774)
    at jcifs.smb.SmbFile.getSecurity(SmbFile.java:2808)
    at TestDeadlock$1.run(TestDeadlock.java:84)
    at java.lang.Thread.run(Thread.java:595)

... other threads stack traces are similar to "Thread-3" above.

Regards
-- Marc
-------------- next part --------------
HTML attachment scrubbed and removed