Re: [PATCH] drm/i915: Move ioremap_wc tracking onto VMA

Tvrtko Ursulin
2016-04-15T10:19:42Z

On 15/04/16 11:00, Chris Wilson wrote:
> On Fri, Apr 15, 2016 at 10:40:42AM +0100, Tvrtko Ursulin wrote:
>>
>> On 13/04/16 16:12, Chris Wilson wrote:
>>> On Wed, Apr 13, 2016 at 03:47:58PM +0100, Chris Wilson wrote:
>>>> + /* We also want to clear any cached iomaps as they wrap vmap */
>>>> + list_for_each_entry_safe(vma, next,
>>>> + &dev_priv->ggtt.base.inactive_list, vm_link)
>>>> + if (vma->iomap && i915_vma_unbind(vma) == 0)
>>>> + freed_pages += vma->node.size >> PAGE_SHIFT;
>>>
>>> Use after free. I need to store the page count in a local before calling
>>> unbind.
>>
>> Waiting for respin. :)
>>
>> Also, shouldn't the patch which adds the size argument to
>> io_mapping_map_wc be in this series?
>
> It was, this was just an update to patch 2. The delta here is just
> unsigned long count = vma->node.size >> PAGE_SHIFT;
> if (vma->iomap && i915_vma_unbind(vma) == 0)
> freed_pages += count;

My bad, I got lost in the threads.. :(

Could I ask for those two BUG_ONs to be replaced with GEM_BUG_ONs now
that is in?

Maybe also add a quick return at the top, as a micro-opt:

if (vma->iomap)
reutrn vma->iomap;

Followed by WARNs, GEM_BUG_ONs and rest?

Shrinker fix mandatory and with or without my above comments r-b from me.

Regards,

Tvrtko