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Date: Tue, 21 Apr 2015 12:17:49 +0200
Message-ID: <CANq1E4SzeDKmF15T-CeOgPcJ-5a6_eM_buEW44nmJsrvBf_fJw@mail.gmail.com>
Subject: Re: [GIT PULL] kdbus for 4.1-rc1
From: David Herrmann <dh.herrmann@gmail.com>
To: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Andy Lutomirski <luto@amacapital.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Richard Weinberger <richard@nod.at>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Steven Rostedt <rostedt@goodmis.org>, Jiri Kosina <jkosina@suse.cz>,
        Al Viro <viro@zeniv.linux.org.uk>, Borislav Petkov <bp@alien8.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Tom Gundersen <teg@jklm.no>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Daniel Mack <daniel@zonque.org>, Djalal Harouni <tixxdz@opendz.org>
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Hi

On Tue, Apr 21, 2015 at 11:35 AM, One Thousand Gnomes
<gnomes@lxorguk.ukuu.org.uk> wrote:
>> On top of that, I think that someone into resource management needs to
>> seriously consider whether having a broadcast send do get_user_pages
>> or the equivalent on pages supplied by untrusted recipients (plural!)
>> is a good idea.
>
> Oh but its so much fun if you pass pages belonging to a device driver, or
> pass bits of a GEM object thereby keeping entire graphics textures
> referenced 8)

We do not use GUP, nor do we pass around pinned pages. All we use is
__vfs_read() / __vfs_write() on shmem. Whether generic_file_write() /
copy_from_user() internally relies on GUP or not, is an orthogonal
issue that does not belong here.

Thanks
David
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