Mailing-List:	contact cygwin-help AT sourceware DOT cygnus DOT com; run by ezmlm
List-Subscribe:	<mailto:cygwin-subscribe AT sources DOT redhat DOT com>
List-Archive:	<http://sources.redhat.com/ml/cygwin/>
List-Post:	<mailto:cygwin AT sources DOT redhat DOT com>
List-Help:	<mailto:cygwin-help AT sources DOT redhat DOT com>, <http://sources.redhat.com/ml/#faqs>
Sender:	cygwin-owner AT sources DOT redhat DOT com
Delivered-To:	mailing list cygwin AT sources DOT redhat DOT com
Message-ID:	<001501c0e3d8$9a4e07a0$7f291518@CX535256E>
From:	"Barubary" <barubary AT home DOT com>
To:	<cygwin AT cygwin DOT com>
Subject:	Device driver incompatible with Cygwin
Date:	Wed, 23 May 2001 15:35:00 -0700
MIME-Version:	1.0
X-Priority:	3
X-MSMail-Priority:	Normal
X-Mailer:	Microsoft Outlook Express 5.50.4522.1200
X-MimeOLE:	Produced By Microsoft MimeOLE V5.50.4522.1200

My strange problems involving fork() and Win2000 have been found.  It is
actually caused by the presence of a device driver I wrote called totalio.

Totalio is a driver which grants direct access to x86 I/O ports to user mode
programs.  It is different from other such drivers in that it only grants
access to *specific* I/O ports (PSX comm link / dreamcast serial card).
Thus, it does not compromise system security, for access to these ports is
harmless.  How it does this is by setting a "create process" hook in kernel
mode which sets the new process's I/O access bitmap.

I believe that the problem is in the undocumented NTOSKRNL function
Ke386IoSetAccessProcess.  I think a memory leak is occurring.  Cygwin isn't
doing anything that would cause this specifically - it just creates
processes far more often than normal Windows programs would.  Running make
on GCC creates thousands of processes, which could easily exhaust the
non-paged pool if there is a memory leak in Ke386IoSetAccessProcess where
the memory isn't freed when a process terminates.

I think this is a bug in Win2000, but since the function is undocumented, I
doubt Microsoft would do anything to fix it.  Any ideas?

-- Barubary


--
Want to unsubscribe from this list?
Check out: http://cygwin.com/ml/#unsubscribe-simple

- Raw text -