Crash in intel_iommu_assign_device

[Jan Kiszka]

Hi Sheng,

I'm not claiming to understand the details, but this looks like use
(dereference of pte via dma_pte_addr) after release (free_pgtable_page
of dmar_domain->pgd aka pte) to me:

static int intel_iommu_attach_device(struct iommu_domain *domain,
                                     struct device *dev)
{
        [...]
                pte = dmar_domain->pgd;
                if (dma_pte_present(pte)) {
                        free_pgtable_page(dmar_domain->pgd);
                        dmar_domain->pgd = (struct dma_pte *)
                                phys_to_virt(dma_pte_addr(pte));
                }

At least it crashes here right on pte->val access. Swap both lines?

Jan

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