Re: [PATCH] Fix IB va_start+ib_bytes range check on 32Bit systems

[Christian KÃnig]

Am 29.03.2017 um 16:54 schrieb Michel DÃnzer:
> On 29/03/17 10:22 PM, Christian KÃnig wrote:
> > Am 29.03.2017 um 11:18 schrieb Jan Burgmeier:
> > > Signed-off-by: Jan Burgmeier <jan.burgmeier@xxxxxxxxxxxxxxxxxxx>
> > > ---
> > >    drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 4 +++-
> > >    1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > > b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > > index 99424cb8020b..583d22974e14 100644
> > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > > @@ -908,6 +908,7 @@ static int amdgpu_cs_ib_fill(struct amdgpu_device
> > > *adev,
> > >                struct amdgpu_bo *aobj = NULL;
> > >                uint64_t offset;
> > >                uint8_t *kptr;
> > > +            uint64_t it_last;
> > >                  m = amdgpu_cs_find_mapping(parser, chunk_ib->va_start,
> > >                               &aobj);
> > > @@ -916,8 +917,9 @@ static int amdgpu_cs_ib_fill(struct amdgpu_device
> > > *adev,
> > >                    return -EINVAL;
> > >                }
> > >    +            it_last = m->it.last;
> > >                if ((chunk_ib->va_start + chunk_ib->ib_bytes) >
> > > -                (m->it.last + 1) * AMDGPU_GPU_PAGE_SIZE) {
> > > +                (it_last + 1) * AMDGPU_GPU_PAGE_SIZE) {
> > Nice catch, but just adding a u64 case should do here as well. E.g:
> >
> > if ((chunk_ib->va_start + chunk_ib->ib_bytes) >
> >      (u64)(m->it.last + 1) * AMDGPU_GPU_PAGE_SIZE) {
> That won't work correctly if m->it.last == 0xffffffff ? Or is that not
> possible?
Hui, why? is it.last signed?

And even then m->it.last probably won't ever become 0xffffffff on a 
32bit system.

BTW: We need to fix using the 64bit R/B tree instead of the long sized 
tree for Vega10 here anyway.

Regards,
Christian.