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Date: Tue, 10 Jul 2001 16:15:33 +0200
From: Andrea Arcangeli <andrea@suse.de>
To: Andrew Morton <andrewm@uow.edu.au>
Cc: Chris Wedgwood <cw@f00f.org>,
        Linux Kernel Development <linux-kernel@vger.kernel.org>
Subject: Re: msync() bug
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In-Reply-To: <3B4B0B1F.92EC5C0E@uow.edu.au>; from andrewm@uow.edu.au on Wed, Jul 11, 2001 at 12:03:11AM +1000
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On Wed, Jul 11, 2001 at 12:03:11AM +1000, Andrew Morton wrote:
> Linus included the test for non-null page->mapping
> as well.  I wonder why.

I think it is because if you try hard you can map a dma page via
/dev/mem and then the driver can release the dma page (at rmmod for
example) before you munmap /dev/mem, and then the page goes in the
freelist and it is allocated as pagecache.

Andrea
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