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    SubjectRe: [PULL] vhost: cleanups and fixes
    On Fri, Nov 2, 2018 at 9:59 AM Michael S. Tsirkin <mst@redhat.com> wrote:
    >
    > Just for completeness I'd like to point out for vhost the copies are
    > done from the kernel thread. So yes we can switch to copy_to/from_user
    > but for e.g. 32-bit userspace running on top of a 64 bit kernel it is
    > IIUC not sufficient - we must *also* do access_ok checks on control path
    > when addresses are passed to the kernel and when current points to the
    > correct task struct.

    Don't you take over the VM with "use_mm()" when you do the copies? So
    yes, it's a kernel thread, but it has a user VM, and though that
    should have the user limits.

    No?

    Linus

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