[jcifs] Possible deadlocking between jcifs.smb.Dfs and jcifs.smb.SmbTransport

Xavier Roche roche+kml2 at exalead.com
Mon Mar 5 00:00:23 MST 2012

On 03/05/2012 04:20 AM, Michael B Allen wrote:
> No. It is not ok to use the same SmbFile instance with more than one
> thread at a time. You can use multiple threads but you just can't use
> the same SmbFile object with multiple threads at the same time.

Okay, noted.

> Are you seeing the deadlock with different SmbFile instances or is it
> only when trying to use the same SmbFile object with multiple threads?

I am seeing the same deadlock, even when using a single SmbFile on each 
thread, when accessing the same DFS tree. (I even synchronized all calls 
to SmbFile to ensure that there was no reentrancy issue)

If I am not mistaken, the way to reproduce the issue is to have multiple 
threads working with *different* files, but inside a *common* DFS (the 
files were created by the same listFiles() probably).

A small torture test (32 threads) will typically deadlock within 

[ A "regular" program would also deadlock, but more "randomly"/slowly. ]

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