From: Federico Vaga <federico.vaga@gmail.com>
Date: Sat, 29 Oct 2011 07:45:39 +0000 (+0200)
Subject: Staging: comedi: fix mmap_count
X-Git-Tag: v3.2-rc5~51^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=df30b21cb0eed5ba8a8e0cdfeebc66ba8cde821d;p=pandora-kernel.git

Staging: comedi: fix mmap_count

In comedi_fops, mmap_count is decremented at comedi_vm_ops->close but
it is not incremented at comedi_vm_ops->open. This may result in a negative
counter.  The patch introduces the open method to keep the counter
consistent.

The bug was triggerd by this sample code:

        mmap(0, ...., comedi_fd);
        fork();
        exit(0);

Acked-by: Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

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