[Mesa-dev] [PATCH] clover: Fix host access validation for sub-buffer creation

[Aaron Watry]

On Mon, Apr 16, 2018, 5:24 PM Francisco Jerez <currojerez at riseup.net> wrote:

> Aaron Watry <awatry at gmail.com> writes:
>
> >   From CL 1.2 Section 5.2.1:
> >     CL_INVALID_VALUE if buffer was created with CL_MEM_HOST_WRITE_ONLY
> and
> >     flags specify CL_MEM_HOST_READ_ONLY , or if buffer was created with
> >     CL_MEM_HOST_READ_ONLY and flags specify CL_MEM_HOST_WRITE_ONLY , or
> if
> >     buffer was created with CL_MEM_HOST_NO_ACCESS and flags specify
> >     CL_MEM_HOST_READ_ONLY or CL_MEM_HOST_WRITE_ONLY .
> >
> > Fixes CL 1.2 CTS test/api get_buffer_info
> >
>
> What combination of flags is the test-case providing for both the
> parent and sub buffer?
>

The original motivation for this was a CTS test that was creating a sub
buffer with flags of:
CL_MEM_HOST_NO_ACCESS | CL_MEM_READ_WRITE

With a parent buffer created as:
CL_MEM_HOST_READ_ONLY | CL_MEM_READ_WRITE

Which according to my reading of the spec should be allowed.

>
> > Signed-off-by: Aaron Watry <awatry at gmail.com>
> > Cc: Francisco Jerez <currojerez at riseup.net>
> > ---
> >  src/gallium/state_trackers/clover/api/memory.cpp | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/gallium/state_trackers/clover/api/memory.cpp
> b/src/gallium/state_trackers/clover/api/memory.cpp
> > index 9b3cd8b1f5..451e8a8c56 100644
> > --- a/src/gallium/state_trackers/clover/api/memory.cpp
> > +++ b/src/gallium/state_trackers/clover/api/memory.cpp
> > @@ -57,10 +57,14 @@ namespace {
> >                                        parent.flags() &
> host_access_flags) |
> >                                       (parent.flags() & host_ptr_flags));
> >
> > -         if (~flags & parent.flags() &
> > -             ((dev_access_flags & ~CL_MEM_READ_WRITE) |
> host_access_flags))
> > +         if (~flags & parent.flags() & (dev_access_flags &
> ~CL_MEM_READ_WRITE))
> >              throw error(CL_INVALID_VALUE);
> >
> > +         //Check if new host access flags cause a mismatch between
> host-read/write-only.
> > +         const cl_mem_flags new_flags = flags & ~(parent.flags()) &
> ~CL_MEM_HOST_NO_ACCESS;
> > +         if (new_flags & host_access_flags & parent.flags())
> > +            throw error (CL_INVALID_VALUE);
> > +
>
> This doesn't look correct to me, the condition will always evaluate to
> zero, you're calculating the conjunction of ~parent.flags() and
> parent.flags() which is zero, so the error will never be emitted.
>

I'll see what I can do. I agree with a fresh reading that it looks fishy at
best.

--Aaron

>
> >           return flags;
> >
> >        } else {
> > --
> > 2.14.1
>
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