[Intel-gfx] [PATCH 4/5] drm/i915: Reject attempted pwrites into a read-only object

[Chris Wilson]

Quoting Joonas Lahtinen (2018-06-01 11:19:07)
> On Thu, 2018-05-31 at 12:35 +0100, Chris Wilson wrote:
> > If the user created a read-only object, they should not be allowed to
> > circumvent the write protection using the pwrite ioctl.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Jon Bloomfield <jon.bloomfield at intel.com>
> > Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > Cc: Matthew Auld <matthew.william.auld at gmail.com>
> 
> This asks for some igt's and selftests.

uABI, so hard for a selftest. (Or more to the point, I haven't figured
out how we are supposed to fake userspace memory from inside the kernel.
set_fs()? Maybe fork_usermode_helper? Hmm. So really I've been focusing
on uABI coverage in igt, and forcing the corner cases in selftests where
we can control faults much more easily.) The first round of igt was
already posted; the plan was to extend that test to cover poking at it
through the different holes in the uapi.
-Chris