Re: [PATCH v6 10/25] iommufd/viommu: Add IOMMUFD_CMD_HW_QUEUE_ALLOC ioctl

On Sat, Jun 14, 2025 at 12:14:35AM -0700, Nicolin Chen wrote:

• /*

• * FIXME allocation may fail when sizeof(*pages) * max_npages is
  

• * larger than PAGE_SIZE. This might need a new API returning a
  

• * bio_vec or something more efficient.
  

• */
  

• pages = kcalloc(max_npages, sizeof(*pages), GFP_KERNEL);

Use the kvcalloc variation here then. You probably also need a GFP_NOWARN to avoid syzkaller blowups.

• access = iommufd_hw_queue_alloc_phys(cmd, viommu, &base_pa);
• if (IS_ERR(access)) {

• rc = PTR_ERR(access);
  

• goto out_put_viommu;
  

• }
• hw_queue = (struct iommufd_hw_queue *)_iommufd_object_alloc_ucmd(

• ucmd, hw_queue_size, IOMMUFD_OBJ_HW_QUEUE);
  

• if (IS_ERR(hw_queue)) {

• rc = PTR_ERR(hw_queue);
  

• goto out_destroy_access;
  

• }

I think these two are out of order, alloc the object first, then do the access and set hw_queue->access. Make sure abort will clean it up automatically when non-null and remove the out_destroy_access

Jason