From owner-freebsd-hackers@FreeBSD.ORG  Mon Feb  3 21:20:51 2014
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Date: Mon, 3 Feb 2014 14:01:00 -0700 (MST)
From: Chris Torek <torek@elf.torek.net>
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To: freebsd-hackers@freebsd.org, rysto32@gmail.com
Subject: Re: Races in ichsmb(9) when accessed from a multithreaded process
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Yes, we found that the code does not properly allow either
multiple threads *or* multiple processes to work.  The top level
driver makes it a single-open device (which has the obvious
drawback that only one process can open() the device).  But even
then, multiple threads within a process, or forking, or using
PF_LOCAL sockets to hand over the file descriptor, result in
races.

We have a hack that makes it work for our case but the SMB
framework needs an overhaul.

Chris