Re: [PATCH v3 1/1] iommu/sva: Invalidate KVA range on kernel TLB flush

[Dave Hansen <dave.hansen@intel.com>]

On 8/6/25 08:52, Jason Gunthorpe wrote:
>> Isn't that still a use-after-free? It's for some arbitrary amount of
>> time and better than before but it's still a use-after-free.
> Yes it is.
> 
> You can't do this approach without also pushing the pages to freed on
> a list and defering the free till the work. This is broadly what the
> normal mm user flow is doing..

FWIW, I think the simplest way to do this is to plop an unconditional
schedule_work() in pte_free_kernel(). The work function will invalidate
the IOTLBs and then free the page.

Keep the schedule_work() unconditional to keep it simple. The
schedule_work() is way cheaper than all the system-wide TLB invalidation
IPIs that have to get sent as well. No need to add complexity to
optimize out something that's in the noise already.