[Intel-gfx] [PATCH 1/2] drm/i915/gvt: Avoid use-after-free iterating the gtt list

[Chris Wilson]

Quoting Zhenyu Wang (2018-11-21 02:29:21)
> On 2018.11.20 20:24:38 +0000, Chris Wilson wrote:
> > Found by smatch:
> > 
> > drivers/gpu/drm/i915/gvt/gtt.c:2452 intel_vgpu_destroy_ggtt_mm() error: dereferencing freed memory 'pos'
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/gvt/gtt.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
> > index 58e166effa45..c7103dd2d8d5 100644
> > --- a/drivers/gpu/drm/i915/gvt/gtt.c
> > +++ b/drivers/gpu/drm/i915/gvt/gtt.c
> > @@ -2447,10 +2447,11 @@ static void intel_vgpu_destroy_all_ppgtt_mm(struct intel_vgpu *vgpu)
> >  
> >  static void intel_vgpu_destroy_ggtt_mm(struct intel_vgpu *vgpu)
> >  {
> > -     struct intel_gvt_partial_pte *pos;
> > +     struct intel_gvt_partial_pte *pos, *next;
> >  
> > -     list_for_each_entry(pos,
> > -                     &vgpu->gtt.ggtt_mm->ggtt_mm.partial_pte_list, list) {
> > +     list_for_each_entry_safe(pos, next,
> > +                              &vgpu->gtt.ggtt_mm->ggtt_mm.partial_pte_list,
> > +                              list) {
> >               gvt_dbg_mm("partial PTE update on hold 0x%lx : 0x%llx\n",
> >                       pos->offset, pos->data);
> >               kfree(pos);
> 
> Reviewed-by: Zhenyu Wang <zhenyuw at linux.intel.com>

I presume you will take it via the gvt tree? Saves a backmerge for you.
-Chris