Re: [PATCH] drm/i915/gvt/scheduler: fix potential NULL pointer dereference

[Gustavo A. R. Silva]

On 03/19/2018 04:23 PM, Chris Wilson wrote:
> Quoting Gustavo A. R. Silva (2018-03-19 20:50:12)
> > Hi Chris,
> >
> > On 03/19/2018 03:38 PM, Chris Wilson wrote:
> > > Quoting Gustavo A. R. Silva (2018-03-19 19:30:53)
> > > > _workload_ is being dereferenced before it is null checked, hence
> > > > there is a potential null pointer dereference.
> > > >
> > > > Fix this by moving the pointer dereference after _workload_ has
> > > > been null checked.
> > >
> > > The checks are misleading and not required.
> >
> > All of them?
> >
> > if (!workload || !reg_state || workload->ring_id != RCS)
> >          return;
>
> workload can not be NULL (dereference in caller), reg_state can not be
> NULL (by construct from kmap()).
>
> It may be not an RCS ring through

I got it.

I'll send the following patch then:

--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -74,7 +74,7 @@ static void sr_oa_regs(struct intel_vgpu_workload 
*workload,
                i915_mmio_reg_offset(EU_PERF_CNTL6),
        };

-       if (!workload || !reg_state || workload->ring_id != RCS)
+       if(workload->ring_id != RCS)
                return;

        if (save) {


Thanks
--
Gustavo