Re: [GIT PULL] kdbus for 4.1-rc1

David Herrmann
2015-04-21T10:17:51Z

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