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

[Zhenyu Wang]

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>

Thanks! I should really run check against each one when apply..

-- 
Open Source Technology Center, Intel ltd.

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